## Reading the Comics, September 17, 2018: Hard To Credit Edition

Two of the four comic strips I mean to feature here have credits that feel unsatisfying to me. One of them is someone’s pseudonym and, yeah, that’s their business. One is Dennis the Menace, for which I find an in-strip signature that doesn’t match the credentials on Comics Kingdom’s web site, never mind Wikipedia. I’ll go with what’s signed in the comic as probably authoritative. But I don’t like it.

R Ferdinand and S Ketcham’s Dennis the Menace for the 16th is about calculation. One eternally surprising little thing about calculators and computers is that they don’t do anything you can’t do by hand. Or, for that matter, in your head. They do it faster, typically, and more reliably. They can seem magical. But the only difference between what they do and what we do is the quantity with which they do this work. You can take this as humbling or as inspirational, as fits your worldview.

Ham’s Life on Earth for the 16th is a joke about the magical powers we attribute to mathematics. It’s also built on one of our underlying assumptions of the world, that it must be logically consistent. If one has an irrefutable logical argument that something isn’t so, then that thing must not be so. It’s hard to imagine how an illogical world would work. But it is hard not to wonder if there’s some arrogance involved in supposing the world has to square with the rules of logic that we find sensible. And to wonder whether we perceive world consistent with that logic because our expectations frame what we’re able to perceive.

In any case, as we frame logic, an argument’s validity shouldn’t depend on the person making the argument. Or even whether the argument has been made. So it’s hard to see how simply voicing the argument that one doesn’t exist could have that effect. Except that mathematics has got magical connotations, and vice-versa. That’ll be good for building jokes for a while yet.

Mark Anderson’s Andertoons for the 17th is the Mark Anderson’s Andertoons for the week. It’s wordplay, built on the connotation that division is a bad thing. It seems less dire if we think of division as learning how to equally share something that’s been held in common, though. Or if we think of it as learning what to multiply a thing by to get a particular value. Most mathematical operations can be taken to mean many things. Surely division has some constructive and happy interpretations.

Paul Gilligan’s Pooch Cafe for the 17th is a variation of the monkeys-on-keyboards joke. If what you need is a string of nonsense characters then … well, a cat on the keys is at least famous for producing some gibberish. It’s likely not going to be truly random, though. If a cat’s paw has stepped on, say, the ‘O’, there’s a good chance the cat is also stepping on ‘P’ or ‘9’. It also suggests that if the cat starts from the right, they’re more likely to have a character like ‘O’ early in the string of characters and less likely at the end. A completely random string would be as likely to have an ‘O’ at the start as at the end of the string.

And even if a cat on the keyboard did produce good-quality randomness, well. How likely a randomly-generated string of characters is to match a thing depends on the length of the thing. If the meaning of the symbols doesn’t matter, then ‘Penny Lane’ is as good as ‘*2ft,2igFIt’. This is not to say you can just use, say, ‘asdfghjkl’ as your password, at least not for anything that would hurt you if it were cracked. If everyone picked all passwords with no regard for what the symbols meant, these would be. But passwords that seem easy to think get used more often than they should be. It’s not that they’re easier to guess, but that guessing them is more likely to be correct.

Later this week I’ll host this month’s Playful Mathematics Blog Carnival! If you know of any mathematics that teaches or delights or both please share it with me, and we’ll let the world know. Also this week I should finally start my 2018 Mathematics A To Z, explaining words from mathematics one at a time.

And there’ll be another Reading the Comics Post before next Sunday. It and all my other Reading the Comics posts should be at this tag. Other appearances of Dennis the Menace should be at this link. This and other essays mentioning Life On Earth are at this link. The many appearances of Andertoons are at this link And other essays with Pooch Cafe should be at this link. Thanks for reading along.

## My Answer For Who’s The Most Improved Pinball Player

Okay, so writing “this next essay right away” didn’t come to pass, because all sorts of other things got in the way. But to get back to where we had been: we hoped to figure out which of the players at the local pinball league had most improved over the season. The data I had available. But data is always imperfect. We try to learn anyway.

What data I had was this. Each league night we selected five pinball games. Each player there played those five tables. We recorded their scores. Each player’s standing was based on, for each table, how many other players they beat. If you beat everyone on a particular table, you got 100 points. If you beat all but three people, you got 96 points. If ten people beat you, you got 90 points. And so on. Add together the points earned for all five games of that night. We didn’t play the same games week to week. And not everyone played every single week. These are some of the limits of the data.

My first approach was to look at a linear regression. That is, take a plot where the independent variable is the league night number and the dependent variable is player’s nightly scores. This will almost certainly not be a straight line. There’s an excellent chance it will never touch any of the data points. But there is some line that comes closer than any other line to touching all these data points. What is that line, and what is its slope? And that’s easy to calculate. Well, it’s tedious to calculate. But the formula for it is easy enough to make a computer do. And then it’s easy to look at the slope of the line approximating each player’s performance. The highest slope of their performance line obviously belongs to the best player.

And the answer gotten was that the most improved player — the one whose score increased most, week to week — was a player I’ll call T. The thing is T was already a good player. A great one, really. He’d just been unable to join the league until partway through. So nights that he didn’t play, and so was retroactively given a minimal score for, counted as “terrible early nights”. This made his play look like it was getting better than it was. It’s not just a problem of one person, either. I had missed a night, early on, and that weird outlier case made my league performance look, to this regression, like it was improving pretty well. If we removed the missed nights, my apparent improvement changed to a slight decline. If we pretend that my second-week absence happened on week eight instead, I had a calamitous fall over the season.

And that felt wrong, so I went back to re-think. This is dangerous stuff, by the way. You can fool yourself if you go back and change your methods because your answer looked wrong. But. An important part of finding answers is validating your answer. Getting a wrong-looking answer can be a warning that your method was wrong. This is especially so if you started out unsure how to find what you were looking for.

So what did that first answer, that I didn’t believe, tell me? It told me I needed some better way to handle noisy data. I should tell apart a person who’s steadily doing better week to week and a person who’s just had one lousy night. Or two lousy nights. Or someone who just had a lousy season, but enjoyed one outstanding night where they couldn’t be beaten. Is there a measure of consistency?

And there — well, there kind of is. I’m looking at Pearson’s Correlation Coefficient, also known as Pearson’s r, or r. Karl Pearson is a name you will know if you learn statistics, because he invented just about all of them except the Student T test. Or you will not know if you learn statistics, because we don’t talk much about the history of statistics. (A lot of the development of statistical ideas was done in the late 19th and early 20th century, often by people — like Pearson — who were eugenicists. When we talk about mathematics history we’re more likely to talk about, oh, this fellow published what he learned trying to do quality control at Guinness breweries. We move with embarrassed coughing past oh, this fellow was interested in showing which nationalities were dragging the average down.) I hope you’ll allow me to move on with just some embarrassed coughing about this.

Anyway, Pearson’s ‘r’ is a number between -1 and 1. It reflects how well a line actually describes your data. The closer this ‘r’ is to zero, the less like a line your data really is. And the square of this, r2, has a great, easy physical interpretation. It tells you how much of the variations in your dependent variable — the rankings, here — can be explained by a linear function of the independent variable — the league night, here. The bigger r2 is, the more line-like the original data is. The less its result depends on fluke events.

This is another tedious calculation, yes. Computers. They do great things for statistical study. These told me something unsurprising: r2 for our putative best player, T, was about 0.313. That is, about 31 percent of his score’s change could be attributed to improvement; 69 percent of it was noise, reflecting the missed nights. For me, r2 was about 0.105. That is, 90 percent of the variation in my standing was noise. This suggests by the way that I was playing pretty consistently, week to week, which matched how I felt about my season. And yes, we did have one player whose r2 was 0.000. So he was consistent and about all the change in his week-to-week score reflected noise. (I only looked at three digits past the decimal. That’s more precision than the data could support, though. I wouldn’t be willing to say whether he played more consistently than the person with r2 of 0.005 or the one with 0.012.)

Now, looking at that — ah, here’s something much better. Here’s a player, L, with a Pearson’s r of 0.803. r2 was about 0.645, the highest of anyone. The most nearly linear performance in the league. Only about 35 percent of L’s performance change could be attributed to random noise rather than to a linear change, week-to-week. And that change was the second-highest in the league, too. L’s standing improved by about 5.21 points per league night. Better than anyone but T.

This, then, was my nomination for the most improved player. L had a large positive slope, in looking at ranking-over-time. L also also a high correlation coefficient. This makes the argument that the improvement was consistent and due to something besides L getting luckier later in the season.

Yes, I am fortunate that I didn’t have to decide between someone with a high r2 and mediocre slope versus someone with a mediocre r2 and high slope. Maybe this season. I’ll let you know how it turns out.

## Reading the Comics, September 14, 2018: I Already Forgot What I Said About Randolph Itch Edition

Yeah, so remember how like two weeks ago I noticed another Randolph Itch, 2 am repeat? And figured to retire the comic strip from my Reading the Comics routine? Well, then you’re better at this blog than I am. But this time I’ll retire it for sure, rather than waste text I wrote up already.

Tom Toles’s Randolph Itch, 2 am for the 13th is the Roman Numerals joke for the week. IV is a well-established way to write four, although on clock faces IIII is a quite common use. There’s not a really clear reason why this should be. I’m convinced that it’s mostly for reasons of symmetry. IIII comes nearer the length of VIII, across it on the clock face. The subtractive principle, where ‘IV’ means ‘one taken away from five’, wasn’t really a thing until the middle ages. But then neither were clocks like that.

Bill Rechin’s Crock for the 14th is a joke about being bad at arithmetic. And yeah, most instructors wouldn’t accept “a lot” as the answer to 125 times 140. But we can go from approximations to something more precise. The number’s got to be more than 10,000, for example. 125 is more than 100, and 140 is more than 100. So 125 times 140 has to be more than 100 times 100. And then I notice: 125 is a hundred plus a quarter-of-a-hundred. So, 125 times 140 is a hundred times 140 plus a quarter-of-a-hundred times 140. A hundred times 140 is easy: it’s 14,000. A quarter of that? … Is a quarter of 12,000 plus a quarter of 2,000. That’s 3,000 plus 500. So 125 times 140 has to be 14,000 plus 3,000 plus 500. 17,500. My calculator agrees, so I feel pretty good. If this all seems like an ad hoc process, well, it is. But it’s how I can do this in my head.

Yes, the comments at ComicsKingdom include a warning that “using this obscenity called new math he may never be right, but he will never be wrong either”. I mention this for fans of cranky old person comics commentary.

Ted Shearer’s Quincy for the 21st of July, 1979 was rerun the 14th. It expresses the then-common wish for a calculator, which held such promise for making mathematics easy. It does make some kinds of mathematics easy. It especially takes considerable tedium out of mathematics. And it opens up new things to discover. Especially if the calculator lets you put the last thing calculated into a formula. That makes it easy to play with all sorts of iterative processes. They let you find solutions to weird and complicated problems. Or explore beautiful fractals. Figure out what limits work like. Or just notice what’s neat about 3.302775638. They let you get into different things.

Daniel Shelton’s Ben for the 14th has Nicholas doing mathematics homework. And something that couldn’t just be any subject; arranging fractions by size is something worth learning. They do have the peculiar and hard-to-adjust-to property that making the denominator larger, without changing the numerator, makes the entire fraction represent a smaller number. I mean a number closer to zero. So I think sorting fractions a reasonable homework project. Cutting them out and pasting them down seems weird to me. But maybe there’s some benefit in making the project tactile like that.

My Reading the Comics posts make up the bulk of this blog by volume. They should all appear at this link. I really this time mean to retiree Randolph Itch, 2am as a tag, but please enjoy the strip’s appearances at this link. This and other appearances by Crock are at this link. Ted Shearer’s Quincy appears in essays on this link And other appearances by Ben should be at this link. Also I’m surprised to learn there are other essays. I would have bet Ben was a new tag this essay.

## Reading the Comics, September 11, 2018: 60% Reruns Edition

Three of the five comic strips I review today are reruns. I think that I’ve only mentioned two of them before, though. But let me preface all this with a plea I’ve posted before: I’m hosting the Playful Mathematics Blog Carnival the last week in September. Have you run across something mathematical that was educational, or informative, or playful, or just made you glad to know about? Please share it with me, and we can share it with the world. It can be for any level of mathematical background knowledge. Thank you.

Tom Batiuk’s Funky Winkerbean vintage rerun for the 10th is part of an early storyline of Funky attempting to tutor football jock Bull Bushka. Mathematics — geometry, particularly — gets called on as a subject Bull struggles to understand. Geometry’s also well-suited for the joke because it has visual appeal, in a way that English or History wouldn’t. And, you know, I’ll take “pretty” as a first impression to geometry. There are a lot of diagrams whose beauty is obvious even if their reasons or points or importance are obscure.

Dan Collins’s Looks Good on Paper for the 10th is about everyone’s favorite non-orientable surface. The first time this strip appeared I noted that the road as presented isn’t a Möbius strip. The opossums and the car are on different surfaces. Unless there’s a very sudden ‘twist’ in the road in the part obscured from the viewer, anyway. If I’d drawn this in class I would try to save face by saying that’s where the ‘twist’ is, but none of my students would be convinced. But we’d like to have it that the car would, if it kept driving, go over all the pavement.

Bud Fisher’s Mutt and Jeff for the 10th is a joke about story problems. The setup suggests that there’s enough information in what Jeff has to say about the cop’s age to work out what it must be. Mutt isn’t crazy to suppose there is some solution possible. The point of this kind of challenge is realizing there are constraints on possible ages which are not explicit in the original statements. But in this case there’s just nothing. We would call the cop’s age “underdetermined”. The information we have allows for many different answers. We’d like to have just enough information to rule out all but one of them.

John Rose’s Barney Google and Snuffy Smith for the 11th is here by popular request. Jughead hopes that a complicated process of dubious relevance will make his report card look not so bad. Loweezey makes a New Math joke about it. This serves as a shocking reminder that, as most comic strip characters are fixed in age, my cohort is now older than Snuffy and Loweezey Smith. At least is plausibly older than them.

Anyway it’s also a nice example of the lasting cultural reference of the New Math. It might not have lasted long as an attempt to teach mathematics in ways more like mathematicians do. But it’s still, nearly fifty years on, got an unshakable and overblown reputation for turning mathematics into doubletalk and impossibly complicated rules. I imagine it’s the name; “New Math” is a nice, short, punchy name. But the name also looks like what you’d give something that was being ruined, under the guise of improvement. It looks like that terrible moment of something familiar being ruined even if you don’t know that the New Math was an educational reform movement. Common Core’s done well in attracting a reputation for doing problems the complicated way. But I don’t think its name is going to have the cultural legacy of the New Math.

Mark Anderson’s Andertoons for the 11th is another kid-resisting-the-problem joke. Wavehead’s obfuscation does hit on something that I have wondered, though. When we describe things, we aren’t just saying what we think of them. We’re describing what we think our audience should think of them. This struck me back around 1990 when I observed to a friend that then-current jokes about how hard VCRs were to use failed for me. Everyone in my family, after all, had no trouble at all setting the VCR to record something. My friend pointed out that I talked about setting the VCR. Other people talk about programming the VCR. Setting is what you do to clocks and to pots on a stove and little things like that; an obviously easy chore. Programming is what you do to a computer, an arcane process filled with poor documentation and mysterious problems. We framed our thinking about the task as a simple, accessible thing, and we all found it simple and accessible. Mathematics does tend to look at “problems”, and we do, especially in teaching, look at “finding solutions”. Finding solutions sounds nice and positive. But then we just go back to new problems. And the most interesting problems don’t have solutions, at least not ones that we know about. What’s enjoyable about facing these new problems?

One thing that’s not a problem: finding other Reading the Comics posts. They should all appear at this link. Appearances by the current-run and the vintage Funky Winkerbean are at this link. Essays with a mention of Looks Good On Paper are at this link. Meanwhile, essays with Mutt and Jeff in the are at this link. Other appearances by Barney Google and Snuffy Smith — current and vintage, if vintage ever does something on-topic — are at this link. And the many appearances by Andertoons are at this link, or just use any Reading the Comics post, really. Thank you.

## Reading the Comics, September 7, 2018: The Playful Mathematics Blog Carnival Is Coming Edition

I’d like to add something to my roundup up of last week’s mathematically-themed comic strips. That thing is a reminder that I’m hosting this month’s Playful Mathematics Education Carnival. It’ll post the last week of September. If you’ve recently seen pages that teach, that play games, that show any kind of mathematics that makes you smile, please, let me know. It’s worth sharing with more people.

Tom Gammill’s The Doozies for the 6th is the Venn Diagrams joke for the week. It’s only a two-circle diagram, but the comic strip hasn’t got that large a cast. And, really, would be hard to stage in a way that made the joke communicable with three or four participants.

Phil Dunlap’s Ink Pen rerun for the 7th showcases arithmetic as a putative superpower. I would agree with Dynaman that at least this addition doesn’t show off superpowers. But there are feats of arithmetic that do seem superhuman. Mathematical pop histories often mention people who could do quite complicated calculations in their head. Some of them were also great mathematicians, like Carl Friedrich Gauss, Leonhard Euler, or Srinivasa Ramanujan. Some were just … very good at calculating. Zacharias Dase is a famous 19th century example. He’s reported as having been able to multiply together two hundred-digit numbers, in his head. The process took nine hours.

Is that superhuman? Well, obviously, literally not. But it’s beyond what most of us could imagine doing. I admit I can’t imagine keeping anything straight in my head for nine hours. But. The basic rules of addition aren’t that exotic. Even a process like finding square roots can be done as additions and divisions and multiplications. Much of what makes this look hard is memory. How do you keep track of a hundred or so partial results each of a hundred or so digits? Much of what else is hard is persistence. How do you keep going after the seventh hour of this? And both are traits that you can develop, and practice, and at least get a little better on.

Or bypass the hard work. If asked 235 plus 747 I’d at least answer “a bit under a thousand”, which isn’t bad for an instant answer. 235 is a little under 250; 747 a little under 750; and 250 plus 750 is easy. Rewrite 235 as 250 – 15, and 747 as 750 – 3, and you have this: 235 + 747 is 250 + 750 – 15 – 3. So that’s 1000 minus 18. 982, pretty attainable. This takes practice. It amounts to learning how to spot an easy problem that looks like the question you actually have.

Greg Evans’s Luann Againn for the 7th shows a date living up to its potential as a fiasco. But it’s not a surprise Gunther finds himself comfortable talking trigonometry. The subject is not one that most people find cozy. I’d guess most people on introduction see it as some weird hybrid that fuses the impenetrable diagrams of geometry with the baffling formulas of algebra.

But there’s comfort in it, especially to a particular personality type. There are a lot of obscure things making up trigonometry. But there’s this beauty, too. All the basic trigonometry functions are tied together in neat little pairs and triplets. Formulas connect the properties of an angle with those of its half and its double. There’s a great many identities, particular calculations that have the same value for every angle.

You can say that about anything, of course. Any topic humans study has endless fascination. What makes mathematical fields comfortable? For one, that they promise this certain knowability. Trigonometry has a jillion definitions and rules and identities and all that. But that means you have a great many things of absolute reliability. They offer this certainty that even “hard” sciences like physics don’t have. Far more security than you see with the difficult sciences, like biology or sociology. And true dependability, compared to the mystifying and obscure rules of interacting with other humans. If you don’t feel you know how to be with people, and don’t feel like you could ever learn, a cosecant is at least something you can master.

I tag my Reading the Comics postsso that you can find as many of them as you like at this link. As long as I’ve written as many as you like. Essays in which I mention The Doozies are at this link. Or will be; turns out this is a new tag. Huh. Essays that discuss Ink Pen are at this link. And essays which mention Luann, either current or vintage, are at this link. Thanks for reading whatever you do enjoy.

## Reading the Comics, September 5, 2018: Single Name Edition

For the second part of last week’s comics, there’s several strips whose authors prefer to use a single name. I’m relieved. Somehow my writing seems easier when I don’t have a long authorial credit to give. I can take writing “Zach Weinersmith” fourteen times a week. It’s all those appearances of, like, “Corey Pandolph and Phil Frank and Joe Troise” (The Elderberries) that slow me way up.

Darrin Bell’s Candorville for the 4th shows off one of the things statistics can do. Tracking some measurable thing lets one notice patterns. These patterns might signify something important. At the least they can suggest things that deserve more scrutiny. There’s dangers, of course. If you’re measuring something that’s rare, or that naturally fluctuates a lot, you might misinterpret changes. You could suppose the changes represent some big, complicated, and invariably scary pattern that isn’t actually there. You can take steps to avoid how much weight you give to little changes. For example, you could look at running averages. Instead of worrying about how often Lemont has asked for his clippers this year versus last, look at how often he’s asked for it, on average, each of the last three years, compared to the average of the three years before that. Changes in that are more likely to be meaningful. But doing this does mean that a sudden change, or a slight but persistent change, is harder to notice. There are always mistakes to be made, when analyzing data. You have to think about what kinds of mistakes you would rather make, and how likely you want to make them.

C-Dog talks about fitting Lemont’s hair growth to a curve. This means looking at the data one has as points in space. What kinds of curves will come as close as possible to including all those points? It turns out infinitely many curves will, and you can fit a curve to all the data points you have. (Unless you have some inconsistent data, like, in 2017 Lemont asked both 14 times and 18 times.) So to do an interpolation you need to make some suppositions. Suppose that the data is really a straight line, with some noise in it. Or is really a parabola. Really a sine wave. Or, drawing from a set of plausible curves, which of those best fits the data?

The Bézier Curve mentioned here is a family of shapes. They’re named for Pierre Bézier, an engineer with Renault who in the 1950s pioneered the using of these curves. There are infinitely many of them. But they’re nice to work with. You can make great-looking curves as sharply curved or as smoothly curved as you like, using them. Most modern fonts use Bézier Curves to compute the shapes of letters. If you have a drawing program, it’s got some kind of Bézier curve in there. It’s the weird tool with a bunch of little dots, most of which are nowhere near the curve they draw. But moving the dots changes the way the curve looks.

A Bézier curve can be linear; indeed, it can just be a line. C-Dog’s showing off by talking about a linear Bézier curve. Or he means something that looks a lot like a line, to the casual eye. Negative-sloped means what it would in high school algebra when you talk about lines: it’s a thing with a value that decreases as the independent variable increases. Something getting rarer in time, for example.

Samson’s Dark Side of the Horse for the 4th is our Roman Numerals joke for the week. The Roman Numerals scheme has well-defined letters to represent the numbers up to 1,000. It doesn’t really have consistent schemes past that. But then the Roman Numeral scheme was a bit more ad hoc than really seems comfortable, to us. There could be a striking variety of ways to write larger numbers, particularly; MathWorld notes how letters like I or X or C would be framed in different ways to get at huge numbers like a hundred thousand or so. Roman Numerals standardized in the middle ages, long after the Roman Empire had reason to care about them, and for that matter as Arabic numerals got to be more accepted. Wikipedia also lists a bunch of Medieval abbreviations in a Roman Numerals scheme for things we just don’t use, like F for 40 or T for 160. I presume they have abundant manuscript examples of these, so that we aren’t making too much out of one person’s idiosyncratic notes.

Thaves’s Frank and Ernest for the 5th uses arithmetic, particularly simple addition, as emblematic of the basics of life. Hard to argue that this isn’t some of the first things anyone would learn, and that mathematics as it’s taught builds from that. A mathematician might see other fields — particularly set theory and category theory — as more fundamental than arithmetic. That is, that you can explain arithmetic in terms of set theory, and set theory in terms of category theory. So one could argue that those are the more basic. But if we mean basic as in the first things anyone learns, yeah, it’s arithmetic. Definitely.

Kliban’s Kliban Cartoons for the 5th speaks of proofs. A good bit of mathematics is existence proofs, which is to say, showing that a thing with desired properties does exist. Sometimes they actually show you the thing. Such a “constructive proof” — showing how you make an example of the thing — pretty well proves the thing exists. But sometimes the best you can do is show that there is an answer. In any case, an example of a fish would convince all but the most hardcore skeptics that fish do exist.

I do at least one, and often several, Reading the Comics posts each week. They’re at this link. Essays that mention Candorville are at this link. Essays where I discuss Dark Side of the Horse are at this link. Appearances of Frank and Ernest should be at this link. Other essays with Kliban cartoons should be at this link.

## Reading the Comics, September 4, 2018: No Henry This Week Edition

There won’t be, this week, any mathematically-themed comic strips featuring the long-running, Carl Anderson-created character Henry. You’ll come to see why I find this worth mentioning soon enough. Not today.

Hart, Mastroianni, and Parker’s Wizard of Id for the 2nd features the blackboard full of symbols to represent the difficult and unsolved problem. And sometimes it does seem like it takes magic to solve an equation. That magic usually takes the form of a transformation. That is, we find a way to rewrite the problem as something different, and find that this different problem is solvable. And then that the solution to this altered problem can be transformed into a solution of the original. This is normal magic, the kind any trained mathematician can do, if haltingly. But sometimes it’ll be just a stroke of imaginative genius, solving a problem that seems at first to have nothing to do with the original. This is genius work, and we all hope we can find a problem on which we can do that.

I can also take the strip to represent one of those things I’m curmudgeonly about. That is that I tend to look at big special-effects-laden attempts to make mathematics look beautiful as … well, they’re nice. But I don’t think they help anyone learn how to do anything. So that the Wizard’s work doesn’t actually solve the problem feels true to me.

Bud Blake’s Tiger rerun for the 3rd is an exclusive peek into my experience every time I decide to finally learn non-Euclidean geometry properly.

Mort Walker and Dik Browne’s vintage Hi and Lois for the 3rd sees Chip struggling with mathematics. His father has a noble idea, that it’ll be easier if he tries to see the problems as fun puzzles. Maybe so, but I agree with Chip: there’s not a punch line to 246 &div; 3. Also, points to Chip for doing that division right away. Clearly he isn’t bad at arithmetic; he just doesn’t like it. We’ve all got things like that.

Hector D Cantu and Carlos Castellanos’s Baldo for the 4th is a joke about being helpless with numbers. … Actually, from the phrasing, I’m not positive that Cruz doesn’t mean he got question number 9, or maybe 19, or maybe number 10 wrong. It’s a bit sloppy to not remember which question was, but I certainly know the pain of remembering having done a problem wrong.

My other Reading the Comics posts should appear at this link. Other essays with The Wizard of Id are at this link. More essays with Tiger are at this link. Both current-run and vintage-run Hi and Lois strips are in essays on this link. And Baldo comics should be at this link.

## Reading the Comics, 1 September 2018: Retirement Of A Tag Edition

I figure to do something rare, and retire one of my comic strip tags after today. Which strip am I going to do my best to drop from Reading the Comics posts? Given how many of the ones I read are short-lived comics that have been rerun three or four times since I started tracking them? Read on and see!

Bill Holbrook’s On The Fastrack for the 29th of August continues the sequence of Fi talking with kids about mathematics. My understanding was that she tried to give talks about why mathematics could be fun. That there are different ways to express the same number seems like a pretty fine-grain detail to get into. But this might lead into some bigger point. That there are several ways to describe the same thing can be surprising and unsettling to discover. That you have, when calculating, the option to switch between these ways freely can be liberating. But you have to know the option is there, and where to look for it. And how to see it’ll make something simpler.

Bill Holbrook’s On The Fastrack for the 30th of August gets onto a thread about statistics. The point of statistics is to describe something complicated with something simple. So detail must be lost. That said, there are something like 2,038 different things called “average”. Each of them has a fair claim to the term, too. In Fi’s example here, 73 degrees (Fahrenheit) could be called the average as in the arithmetic mean, or average as in the median. The distribution reflects how far and how often the temperature is from 73. This would also be reflected in a quantity called the variance, or the standard deviation. Variance and standard deviation are different things, but they’re tied together; if you know one you know the other. It’s just sometimes one quantity is more convenient than the other to work with.

Bill Holbrook’s On The Fastrack for the 1st of September has Fi argue that apparent irrelevance makes mathematics boring. It’s a common diagnosis. I think I’ve advanced the claim myself. I remember a 1980s probability textbook asking the chance that two transistors out of five had broken simultaneously. Surely in the earlier edition of the textbook, it was two vacuum tubes out of five. Five would be a reasonable (indeed, common) number of vacuum tubes to have in a radio. And it would be plausible that two might be broken at the same time.

It seems obvious that wanting to know an answer makes it easier to do the work needed to find it. I’m curious whether that’s been demonstrated true. Like, it seems obvious that a reference to a thing someone doesn’t know anything about would make it harder to work on. But does it? Does it distract someone trying to work out the height of a ziggurat based on its distance and apparent angle, if all they know about a ziggurat is their surmise that it’s a thing whose height we might wish to know?

Tom Toles’s Randolph Itch, 2 am rerun for the 30th of August is an old friend that’s been here a couple times. I suppose I do have to retire the strip from my Reading the Comics posts, at least, although I’m still amused enough by it to keep reading it daily. Simon Garfield’s On The Map, a book about the history of maps, notes that the X-marks-the-spot thing is an invention of the media. Robert Louis Stevenson’s Treasure Island particularly. Stevenson’s treasure map, Garfield notes, had to be redrawn from the manuscript and the author’s notes. The original went missing in the mail to the publishers. I just mention because I think that adds a bit of wonder to the treasure map. And since, I guess, I won’t have the chance to mention this again.

Zach Weinersmith’s Saturday Morning Breakfast Cereal for the 30th of August satisfies the need for a Venn Diagram joke this time around. It’s also the strange-geometry joke for the week. Klein bottles were originally described by Felix Klein. They exist in four (or more) dimensions, in much the way that M&oum;bius strips exist in three. And like the M&oum;bius strip the surface defies common sense. You can try to claim some spot on the surface is inside and some other spot outside. But you can get from your inside to your outside spot in a continuous path, one you might trace out on the surface without lifting your stylus.

If you were four-dimensional. Or more. If we were to see one in three dimensions we’d see a shape that intersects itself. As beings of only three spatial dimensions we have to pretend that doesn’t happen. It’s the same we we pretend a drawing of a cube shows six squares all of equal size and connected at right angles to one another, even though the drawing is nothing like that. The bottle-like shape Weinersmith draws is, I think, the most common representation of the Klein bottle. It looks like a fancy bottle, and you can buy one as a novelty gift for a mathematician. I don’t need one but do thank you for thinking of me. MathWorld shows another representation, a figure-eight-based one which looks to me like an advanced pasta noodle. But it doesn’t look anything like a bottle.

Eric the Circle for the 31st of August, this one by JohnG, is a spot of wordplay. The pun here is the sine of an angle in a (right) triangle. That would be the length of the leg opposite the angle divided by the length of the hypotenuse. This is still stuff relevant to circles, though. One common interpretation of the cosine and sine of an angle is to look at the unit circle. That is, a circle with radius 1 and centered on the origin. Draw a line segment opening up an angle θ from the positive x-axis. Draw it counterclockwise. That is, if your angle is a very small number, you’re drawing a line segment that’s a little bit above the positive x-axis. Draw the line segment long enough that it touches the unit circle. That point where the line segment and the circle intersect? Look at its Cartesian coordinates. The y-coordinate will be the sine of θ. The x-coordinate will be the cosine of θ. The triangle you’re looking at has vertices at the origin; at x-coordinate cosine θ, y-coordinate 0; and at x-coordinate cosine θ, y-coordinate sine θ.

Bill Griffith’s Zippy the Pinhead for the 1st of September is its usual sort of nonsense, the kind that’s up my alley. It does spend two panels using arithmetic and algebra as signifiers of intelligence, or at least thoughtfulness.

My other Reading the Comics posts should appear at this link. Other essays with On The Fastrack are at this link. The essays that mentioned Randolph Itch, 2 am, are at this link, and I suppose this will be the last of them. We’ll see if I do succeed in retiring the tag. Other appearances by Saturday Morning Breakfast Cereal are at this link. The strip comes up here a lot. Eric the Circle comics should be at this link. And other essays with Zippy the Pinhead mentions should be at this link. Thank you.

## I’m Still Looking For Fun Mathematics And Words

I’m hoping to get my 2018 Mathematics A To Z started the last week of September, which among other things will let me end it in 2018 if I haven’t been counting wrong. We’ll see. If you’ve got requests for the first several letters in the alphabet, there’s still open slots. I’ll be opening up the next quarter of the alphabet soon, too.

And also set for the last week of September — boy, I’m glad I am not going to have any doubts or regrets about how I’m scheduling my time for two weeks hence — is the Playful Mathematic Education Carnival. This project, overseen by Denise Gaskins, tries to bring a bundle of fun stuff about mathematics to different blogs. Iva Sallay’s turn, the end of August, is up here. Have you spotted something mathematical that’s made you smile? Please let me know. I’d love to share it with the world.

## How August 2018 Treated My Mathematics Blog

And with the start of the month it’s my chance to do my usual self-examination. In this I look over what was popular, and how popular, and draw no usable conclusions from this. The month didn’t end as I had hoped, owing to family matters. But then nothing ever does quite go as one hopes. We just have to carry on anyway. But looking over WordPress’s review of readership around here:

Huh. August was a busy month, with 1,421 recorded page views. The last several months had been 1,058 and 1,077. This is the third-highest number of page views since April of 2016 at least. And that’s from 913 unique visitors, which is the second-highest number of unique visitors I’ve got on record. (March 2018 continues to taunt me with 999 unique visitors.) People found something they liked.

They liked 57 things, which compares to July’s 37 by being larger. It’s still an anemic total, though. June had 94 likes, and even that is way down from a year ago. August 2017 had 147 likes. And there was a time there’d be 345 likes in a month. That time was April 2016. Comments drifted slightly downward, to 27 from July’s 28 or June’s 30. I count that as holding still, anyway. As ever, I need to do better writing things that encourage responses.

The roster of most popular articles suggests that I’m catching on as a reference for the record-groove counting problem. Just under 200 page views were of that alone. The next-most-popular piece had only 67 views. Don’t think I’m not considering studying power-law scaling of my posts. If you have no idea what I’m on about, don’t worry. I may get to it. But here’s the most popular posts for the past month:

I’m still taking nominations for the A-To-Z, by the way, and shall be for a while yet. Also, discussions of fun mathematics which don’t fit the A-To-Z format may yet belong in the Mathematics Blog Carnival, to appear here at the end of September. Please let me know of anything that’s educational or playful or just fun that you’d like to see shared with more people. Can be your own writing; can be something you think more people should know.

What countries of the world, plus the European Union, sent me readers in August? And how many? Here’s the official roster as WordPress make it out.

United States 802
Philippines 232
Turkey 44
India 40
United Kingdom 31
Australia 30
European Union 26
France 18
Germany 12
Bhutan 8
Italy 7
Singapore 7
Belgium 6
Czech Republic 6
Netherlands 6
Peru 6
Puerto Rico 6
Spain 6
Israel 5
Pakistan 5
Sweden 5
Brazil 4
Finland 4
Mexico 4
New Zealand 4
Nigeria 4
Norway 4
Algeria 3
Indonesia 3
South Africa 3
South Korea 3
United Arab Emirates 3
Denmark 2
Malaysia 2
Vietnam 2
Argentina 1
Austria 1 (*)
Chile 1
Colombia 1
Egypt 1
Estonia 1
Ethiopia 1
Hong Kong SAR China 1
Ireland 1 (*)
Latvia 1
Luxembourg 1
Panama 1
Portugal 1
Romania 1 (*)
Slovenia 1
Sri Lanka 1

They list 52 countries sending me any readers. This is the same as in July. There were 16 single-reader countries, again the same as in July. I know, I’m worried I made a mistake with the data too. Ah, but here. Austria, Ireland, and Romania are on two-month streaks as single-reader countries. Nobody’s been on the roster more than two months in a row. Serbia just missed the half-year milestone.

The Insights panel would have me believe I started September on 66,380 page views, from 32,601 recorded unique visitors. I’ll go along with that gag. For the year to date, I’ve posted — well, I forgot to take a snapshot of the data before Sunday’s Reading the Comics post published. If we pretend the 2nd of September was part of August, though, then: I’ve had 105 posts so far this year; 14 in August and 15 in the Greater August that included this past Sunday. I’ve accumulated 269 total comments, for an average of 2.6 comments per post. This is the same average I had at the start of August. I gathered a total of 633 likes, for an average of 6.0 likes per post this year. Start of August I’d had 6.4 likes per post. Counting Sunday’s post I had 97,634 total words published so far this year, 14,551 of them in August. In July I had 14,032 words in only twelve posts. My words-per-post average is up to 930. Start of August it had drifted down to 885.3.

If you’d like to read my posts you’ve got options. They all involve reading, though. Maybe having them read to you. But all my posts are available by RSS feed. If you like the WordPress reader, there’s a button at the upper-right corner of the page. And if you’d like to see messages announced on Twitter, I’m @Nebusj there. And yes, I am sniffing around Mathstodon.xyz, the mathematics-themed instance of the Twitter-like social site Mastodon. Just browsing its public feed can be fun. There’s a mix of people sharing neat stuff they ran across, little puzzles that’ve been bothering them, and legitimate current research. I do not have an account there and might not make one at all. But I’m thinking about whether I ought. Will tell you if and when I do.

## Reading the Comics, August 29, 2018: The Week I Missed One Edition

Have you ever wondered how I gather comic strips for these Reading the Comics posts? Sure, why not go along with me. Well, I do it by this: I read a lot of comic strips. When I run across one that’s got some mathematical theme, I copy the URL for it over to a page of notes. Then I go back to those notes and write up a paragraph or so on each. That is, I do it exactly the way you might imagine if you weren’t very imaginative or trying hard. I explain all this to say that I made a note that I then didn’t notice. So I missed a comic strip. And opened myself up to wondering if there’s an etymological link between “note” and “notice”. Anyway, it’s here. I’m just explaining why it’s late.

Jim Toomey’s Sherman’s Lagoon for the 19th of August is the belated inclusion. It’s a probability strip. It’s built partly on how badly people estimate probability, especially of rare events. And of how badly people estimate the consequences of rare events. For anything that isn’t common, our feelings about the likelihood of events are garbage. And even for common events we’re not that good.

But then it’s hard to quantify a low-probability event too. Take the claim that a human has one chance in 3.7 million of being attacked by a shark. We’ll pretend that’s the real number; I don’t know what is. (I’m suspicious of the ‘3-7’. People picking a random two-digit number are surprisingly likely to pick 37 because, I guess, it ‘feels’ random.) Is that over their lifetime? Over a summer? In a single swimming event? In any case it’s such a tiny chance it’s not worth serious worry. But even then, a person who lives in Wisconsin and only ever swims in Lake Michigan has a considerably smaller chance of shark attack than a person from New Jersey who swims at the Shore. At least some of these things are probabilities we can affect.

So the fellow may be irrational, denying himself something he’d enjoy based on a fantastically unlikely event. But he is acting to avoid something he’s decided he doesn’t want to risk. And, you know, we all act irrationally at times, or else I couldn’t justify buying a lottery ticket every eight months or so. Also is Fillmore (the turtle) the person who needs to hear this argument?

Gary McCoy and Glenn McCoy’s The Duplex for the 26th is an accounting joke. And a cry about poverty, with the idea that one could make the adding up of one’s assets and debts work only by making mathematics logically inconsistent. Or maybe inconsistent. Arithmetic modulo a particular number could be said to make zero equal to some other number, after all, and that’s all valid. Useful, too, especially in enciphering messages and in generating random numbers. It’s less useful for accounting, though. At least it would draw attention if used unilaterally.

Steve Kelley and Jeff Parker’s Dustin for the 28th is roughly a student-resisting-the-homework problem. From the first panel I thought Hayden might be complaining that ‘x’ was used, once again, as the variable to be solved for. It is the default choice, made because we all grew up learning of ‘x’ as the first choice for a number with a not-yet-known identity. ‘y’ and ‘z’ come in as second and third choices, most likely because they’re quite close to ‘x’. Sometimes another letter stands out, usually because the problem compels it. If the framing of the problem is about when events happen then ‘t’ becomes the default choice. If the problem suggests circular motion then ‘r’ or ‘θ’ — radius and angle — become compelling. But if we know no context, and have only the one variable, then ‘x’ it is. It seems weird to do otherwise.

Bill Holbrook’s On The Fastrack for the 28th is part of a week of Fi talking about mathematics to kids. She occasionally delivers seminars meant to encourage enthusiasm about mathematics. I love the principle although I don’t know how long the effect lasts. (Although it is kind of what I’m doing here. Except I think maybe Fi gets paid.) Holbrook’s strips of this mode often include nice literal depictions of metaphors. This week didn’t offer much chance for that particular artistic play.

I have at least one, and often several, Reading the Comics posts, each week. They should all appear at this link. Other essays with Sherman’s Lagoon will appear at this link when they’re written. I’m surprised to learn that’s a new tag. Essays that mention The Duplex are at this link. Other appearances by Dustin, a character who does not appear in this particular essay’s strips, are at this link. And On The Fastrack mentions should appear at this link. Thank you.

## Reading the Comics, August 24, 2018: Delayed But Eventually There Edition

Now I’ve finally had the time to deal with the rest of last week’s comics. I’ve rarely been so glad that Comic Strip Master Command has taken it easy on me for this week.

Tom Toles’s Randolph Itch, 2am for the 20th is about a common daydream, that of soap bubbles of weird shapes. There’s fun mathematics to do with soap bubbles. Most of these fall into the “calculus of variations”, which is good at finding minimums and maximums. The minimum here is a surface with zero mean curvature that satisfies particular boundaries. In soap bubble problems the boundaries have a convenient physical interpretation. They’re the wire frames you dunk into soap film, and pull out again, to see what happens. There’s less that’s proven about soap bubbles than you might think. For example: we know that two bubbles of the same size will join on a flat common surface. Do three bubbles? They seem to, when you try blowing bubbles and fitting them together. But this falls short of mathematical rigor.

Parker and Hart’s Wizard of Id Classics for the 21st is a joke about the ignorance of students. Of course they don’t know basic arithmetic. Curious thing about the strip is that you can read it as an indictment of the school system, failing to help students learn basic stuff. Or you can read it as an indictment of students, refusing the hard work of learning while demanding a place in politics. Given the 1968 publication date I have a suspicion which was more likely intended. But it’s hard to tell; 1968 was a long time ago. And sometimes it’s just so easy to crack an insult there’s no guessing what it’s supposed to mean.

Gene Mora’s Graffiti for the 22nd mentions what’s probably the most famous equation after that thing with two times two in it. It does cry out something which seems true, that $E = mc^2$ was there before Albert Einstein noticed it. It does get at one of those questions that, I say without knowledge, is probably less core to philosophers of mathematics than the non-expert would think. But are mathematical truths discovered or invented? There seems to be a good argument that mathematical truths are discovered. If something follows by deductive logic from the axioms of the field, and the assumptions that go into a question, then … what’s there to invent? Anyone following the same deductive rules, and using the same axioms and assumptions, would agree on the thing discovered. Invention seems like something that reflects an inventor.

But it’s hard to shake the feeling that there is invention going on. Anyone developing new mathematics decides what things seem like useful axioms. She decides that some bundle of properties is interesting enough to have a name. She decides that some consequences of these properties are so interesting as to be named theorems. Maybe even the Fundamental Theorem of the field. And there was the decision that this is a field with a question interesting enough to study. I’m not convinced that isn’t invention.

Mark Anderson’s Andertoons for the 23rd sees Wavehead — waaait a minute. That’s not Wavehead! This throws everything off. Well, it’s using mathematics as the subject that Not-Wavehead is trying to avoid. And it’s not using arithmetic as the subject easiest to draw on the board. It needs some kind of ascending progression to make waiting for some threshold make sense. Numbers rising that way makes sense.

Scott Hilburn’s The Argyle Sweater for the 24th is the Roman numerals joke for this week. Oh, and apparently it’s a rerun; I hadn’t noticed before that the strip was rerunning. This isn’t a complaint. Cartoonists need vacations too.

That birds will fly in V-formation has long captured people’s imaginations. We’re pretty confident we know why they do it. The wake of one bird’s flight can make it easier for another bird to stay aloft. This is especially good for migrating birds. The fluid-dynamic calculations of this are hard to do, but any fluid-dynamic calculations are hard to do. Verifying the work was also hard, but could be done. I found and promptly lost an article about how heartbeat monitors were attached to a particular flock of birds whose migration path was well-known, so the sensors could be checked and data from them gathered several times over. (Birds take turns as the lead bird, the one that gets no lift from anyone else’s efforts.)

So far as I’m aware there’s still some mystery as to how they do it. That is, how they know to form this V-formation. A particularly promising line of study in the 80s and 90s was to look at these as self-organizing structures. This would have each bird just trying to pay attention to what made sense for itself, where to fly relative to its nearest-neighbor birds. And these simple rules created, when applied to the whole flock, that V pattern. I do not know whether this reflects current thinking about bird formations. I do know that the search for simple rules that produce rich, complicated patterns goes on. Centuries of mathematics, physics, and to an extent chemistry have primed us to expect that everything is the well-developed result of simple components.

Dave Whamond’s Reality Check for the 24th is apparently an answer to The Wandering Melon‘s comic earlier this month. So now we know what kind of lead time Dave Whamond is working on.

My next, and past, Reading the Comics posts are available at this link. Other essays with Randolph Itch, 2 a.m., are at this link. Essays that mention The Wizard of Id, classic or modern, are at this link. Essays mentioning Graffiti are at this link. Other appearances by Andertoons are at this link, or just read about half of all Reading the Comics posts. The Argyle Sweater is mentioned in these essays. And other essays with Reality Check are at this link. And what the heck; here’s other essays with The Wandering Melon in them.

## The Mathematics Carnival is Coming

I apologize for falling even more silent than usual, and shall get to reviewing the past week’s comic strips soon. I had a big pile of life land on me, although, not so big a pile as landed on other people.

But people should know: the last week of the month is the time for the Mathematics Education Blog Carnival. It’s a collection of all sorts of fun mathematics. Educational? Sure. Playful? Sure. Tips? Games? Yes. The host for July was Joshua Greene, of Three J’s Learning. The host for this August is Iva Sallay, whose Find the Factors has been a reliably fun challenge, accompanied by neat little trivia about the whole numbers, for ages now. I hope you can look at her site, and at the carnival (when it posts), and that you enjoy.

And then now I’ve tipped my hand to who’s hosting the carnival for next month, and the last week of September.

## Reading the Comics, August 18, 2018: Ragged Ends Edition

I apologize for the ragged nature of this entry, but I’ve had a ragged sort of week and it’s all I can do to keep up. Alert calendar-watchers might have figured out I would have rather had this posted on Thursday or Friday, but I couldn’t make that work. I’m trying. Thanks for your patience.

Mark Anderson’s Andertoons for the 17th feeds rumors that I just reflexively include Mark Anderson’s Andertoons in these posts whenever I see one. But it features the name of something dear to me, so that’s worthwhile. And I love etymology, although not enough to actually learn anything substantive about it. I just enjoy trivia about where some words come from, and sometimes how they change over time. (The average English word meant the exact opposite thing about two hundred years ago, and it meant something hilariously unrelated two centuries before that.)

So I’m not sure how real word-studyers would regard the “geo” in “geometry”. The word is more or less Ancient Greek, given a bit of age and worn down into common English forms. It’s fair enough to describe it as originally meaning “land survey” or “land measure”. This might seem eccentric. But much of the early use of geometry was to figure out where things were, and how far they were from each other. It seems likely the earliest uses, for example, of the Pythagorean Theorem dealt with how to draw right angles on the surface of the Earth. And how to draw boundaries. The Greek fascination with compass-and-straightedge construction — work done without a ruler, so that you know distance only as a thing relative to other things in your figure — obscures how much of the field is about measurement.

Brett Koth’s Diamond Lil for the 17th is another geometry joke, and a much clearer one. And if there’s one thing we can say about parallel lines it’s that they don’t meet. There are some corners of geometry in which it’s convenient to say they “meet at infinity”, that is, they intersect at some point an infinite distance away. I don’t recommend bringing this up in casual conversation. I’m not sure I wanted to bring it up here.

Johnny Hart’s Back to BC for the 18th is … hm. Well, I’ll call it a numerals joke. It’s part of the continuum of jokes made about ice skating in figure-eights.

Other essays about comic strips are at this link. When I’ve talked about Andertoons I’ve tried to make sure it turns up at this link. Essays in which I’ve discussed Diamond Lil should be at this link when there are other ones. Turns out this is a new tag. The times I’ve discussed B.C., old or new, should be at this link.

## Reading the Comics, August 16, 2018: Recursive Edition

This edition of Reading the Comics can be found at this link.

Zach Weinersmith’s Saturday Morning Breakfast Cereal for the 14th is a fractals joke. Benoit Mandelbrot became the centerpiece of the big fractals boom in pop mathematics in the 80s and 90s. This was thanks to a fascinating property of complex-valued numbers that he discovered and publicized. The Mandelbrot set is a collection of complex-valued numbers. It’s a border, properly, between two kinds of complex-valued numbers. This boundary has this fascinating shape that looks a bit like a couple kidney beans surrounded by lightning. That’s neat enough.

What’s amazing, and makes this joke anything, is what happens if you look closely at this boundary. Anywhere on it. In the bean shapes or in the lightning bolts. You find little replicas of the original shape. Not precisely the original shape. No two of these replicas are precisely identical (except for the “complex conjugate”, that is, something near the number $-1 + 1 \imath$ has a mirror image near $-1 - 1 \imath$). None of these look precisely like the original shape. But they look extremely close to one another. They’re smaller, yes, and rotated relative to the original, and to other copies. But go anywhere on this boundary and there it is: the original shape, including miniature imperfect copies, all over again.

The Mandelbrot Set itself — well, there are a bunch of ways to think of it. One is in terms of something called the Julia Set, named for Gaston Julia. In 1918 he published a massive paper about the iteration of rational functions. That is, start with some domain and a function rule; what’s the range? Now if we used that range as the domain again, and used the same rule for the function, what’s the range of that range? If we use the range-of-that-range as the domain for the same function rule, what’s the range-of-the-range-of-the-range? The particular function here has one free parameter, a single complex-valued number. Depending on what it is, the range-of-the-range-of-the-range-etc becomes a set that’s either one big blob or a bunch of disconnected blobs. The Mandelbrot Set is the locus of parameters separating the one-big-blob from the many-disconnected-blob outcomes.

By the way, yes, Julia published this in 1918. The work was amazing. It was also forgotten. You can study this stuff analytically, but it’s hard. To visualize it you need to do incredible loads of computation. So this is why so much work lay fallow until the 1970s, when Mandelbrot could let computers do incredible loads of computation, and even draw some basic pictures.

Doug Savage’s Savage Chickens for the 14th is another instance of the monkeys-at-typewriters joke. I’ve written about this and the history of the monkeys-at-typewriters bit recently enough to feel comfortable pointing people there. It’s interesting that monkeys should have a connotation of reliably random typewriting, while cats would be reliably not doing something. But that’s a cultural image that’s a little too far from being mathematics for me to spend 800 words discussing.

Thom Bleumel’s Birdbrains for the 15th is a calendars joke. Numbers come into play since, well, it seems odd to try tracking large numbers of dates without some sense of arithmetic. Also, likely, without some sense of geometry. Calendars are much used to forecast coming events, such as New and Full Moons or the seasons. That takes basic understanding of how to locate things in the sky to do at all. It takes sophisticated understanding of how to locate things in the sky to do well.

Scott Hilburn’s The Argyle Sweater for the 16th is the first anthropomorphic-numerals joke around here in like three days. Certainly, the scandalous thing is supposed to be these numbers multiplying out in public where anyone might see them. I wonder if any part of the scandal should be that multiplication like this has to include three partners: the 4, the 7, and the x. In algebra we get used to a convention in which we do without the ‘x’. Just placing one term next to another carries an implicit multiplication: ‘4a’ for ‘4 times a’. But that convention fails disastrously with numerals; what should we make of ’47’? We might write 4(7), or maybe (4)(7), to be clear. Or we might put a little centered dot between the two, $4 \cdot 7$. The ‘x’ by that point is reserved for “some variable whose value isn’t specified”. And it would be weird to write ‘4 times x times 7’. It wouldn’t be wrong; it’d just look weird. It would suggest you were trying to emphasize a point. I’ve probably done it in one of my long derivation-happy posts.

Other essays about comic strips are at this link. When I’ve talked about Saturday Morning Breakfast Cereal I’ve tried to make sure it turns up at this link. Essays in which I’ve discussed Savage Chickens should be at this link. The times I’ve discussed Birdbrains should be at this link. And other essays describing The Argyle Sweater are at this link.

## I’m Looking For Topics For My Fall 2018 Mathematics A-To-Z

So I have given up on waiting for a moment when my schedule looks easier. I’m going to plunge in and make it all hard again. Thus I announce, to start in about a month, my Fall 2018 Mathematics A To Z.

This is something I’ve done once or twice the last few years. The idea is easy: I take one mathematical term for each letter of the alphabet and explain it. The last several rounds I’ve gotten the words from you, kind readers who would love watching me trying to explain something in a field of mathematics I only just learned anything about. It’s great fun. If you do any kind of explanatory blog I recommend the format.

I do mean to do things a little different this time. First, and most visibly, I’m only going to post two essays a week. In past years I’ve done three, and that’s a great pace. It’s left me sometimes with that special month where I have a fresh posting every single day of the month. It’s also a crushing schedule, at least for me. Especially since I’ve been writing longer and longer, both here and on my humor blog. Two’s my limit and I reserve the right to skip a week when I need to skip a week.

Second. I’m going to open for requests only a few letters at a time. In the past I’ve ended up lost when, for example, my submit-your-requests post ends up being seven weeks back and hard to find under all my notifications. This should help me better match up my requests, my writing pace, and my deadlines. It will not.

Also, in the past I’ve always done first-come, first-serve. I’m still inclined toward that. But I’m going to declare that if I come in and check my declarations some morning and find several requests for the same letter, I may decide to go with the word that most captures my imagination. Probably I won’t have the nerve. But I’d like to think I have. I might do some supplementals after the string is done, too. We’ll see what I feel up to. Doing a whole run is exhilarating but exhausting.

So. Now I’d like to declare myself open for the letters ‘A’ through ‘F’. In past A to Z’s I’ve already given these words, so probably won’t want to revisit them. (Though there are some that I think, mm, I could do better now.)

#### Excerpted from The Summer 2017 A To Z

And there we go! … To avoid confusion I’ll mark off here when I have taken a letter.

#### Available Letters for the Fall 2018 A To Z:

•     A
•     B
•     C
• D
•     E
•     F

Oh, I need to commission some header art from Thomas K Dye, creator of the web comic Newshounds, for this. Also for another project that’ll help my September get a little more overloaded.

## Reading the Comics, August 14, 2018: Condensed Books Edition

The title of this installment has nothing to do with anything. My love and I just got to talking about Reader’s Digest Condensed Books and I learned moments ago that they’re still being made. I mean, the title of the series changed from “Condensed Books” to “Select Editions” in 1997, but they’re still going on, as far as anyone can tell. This got us wondering things like how they actually do the abridging. And got me wondering whether any abridged book ended up being better than the original. So I have reasons for only getting partway through last week’s mathematically-themed comics. I don’t say they’re good reasons.

Scott Hilburn’s The Argyle Sweater for the 13th is the Roman Numerals joke for the week, the first one of those in like five days. Also didn’t know that there were still sidewalk theaters that still showed porn movies. I thought they had all been renovated into either respectable neighborhood-revitalization projects that still sometimes show Star Wars films or else become incubator space for startup investment groups.

Corey Pandolph’s The Elderberries for the 13th is a joke about learning fractions. They don’t see to be having much fun thinking about them. Fair enough, I suppose. Once you’ve got the hang of basic arithmetic here come fractions to follow rules for addition and subtraction that are suddenly way more complicated. Multiplication isn’t harder, at least, although it is longer. Same with division. Without a clear idea why this is anything you want to do, yeah, it seems to be unmotivated complicating of stuff.

Dave Whamond’s Reality Check for the 13th is trying to pick a fight with me. I’m not taking the bait. Although by saying ‘likelihood’ the question seems to be setting up a probability question. Those tend to use ‘p’ and ‘q’ as a generic variable name, rather than ‘x’. I bet you imagine that ‘p’ gets used to represent a possibly-unknown ‘probability’ because, oh yeah, first letter. Well … so far as I know that’s why. I’m away from my references right now so I can’t look them over and find no quite satisfactory answer. But that sure seems like it. ‘q’ gets called in if you need a second probability, and don’t want to deal with subscripts, then it’s a nice convenient letter close to ‘p’ in the alphabet. Again, so far as I know.

Thaves’s Frank and Ernest for the 13th is the anthropomorphic-numerals joke for the week.

You can see this and more essays about comic strips by following this link. Other essays describing The Argyle Sweater are at this link. Essays inspired by The Elderberries are at this link. Essays about Reality Check are at this link. And times when I’ve talked about Frank and Ernest you should find at this link.. I can’t be perfectly sure about The Argyle Sweater and The Elderberries because I keep forgetting whether I had decided to include the ‘the’ of their titles as part of their tags. I keep figuring I’ll check which one I’ve used more often and then edit tags to make things consistent. And make a little style guide so that I remember. This will never happen.

## Reading the Comics, August 11, 2018: Strips For The Week Edition

The other half of last week’s mathematically-themed comics were on familiar old themes. I’ll see what I can do with them anyway.

Scott Hilburn’s The Argyle Sweater for the 9th is the anthropomorphic numerals joke for the week. I’m curious why the Middletons would need multiple division symbols, but I suppose that’s their business. It does play on the idea that “division” and “splitting up” are the same thing. And that fits the normal use of these words. We’re used to thinking, say, of dividing a desired thing between several parties. While that’s probably all right in introducing the idea, I do understand why someone would get very confused when they first divide by one-half or one-third or any number between zero and one. And then negative numbers make things even more confusing.

Thaves’s Frank and Ernest for the 9th is the anthropomorphic geometric figures joke for the week. I think I can wrangle a way by which Circle’s question has deeper mathematical context. Mathematicians use the idea of “space” a lot. The use is inspired by how, you know, the geometry of a room works. Euclidean space, in the trade. A Euclidean space is a collection of points that obey a couple simple rules. You can take two points and add them, and get something in the space. You can take any scalar and multiply it by any point and get a point in the space. A scalar is something that acts like a real number. For example, real numbers. Maybe complex numbers, if you’re feeling wild.

A Euclidean space can be two-dimensional. This is the geometry of stuff you draw on paper. It can be three-dimensional. This is the geometry of stuff in the real world, or stuff you draw on paper with shading. It can be four-dimensional. This is the geometry of stuff you draw on paper with big blobby lines around it. Each of these is an equally good space, though, as legitimate and as real as any other. Context usually puts an implicit “three dimensional” before most uses of the word “space”. But it’s not required to be there. There’s many kinds of spaces out there.

And “space” describes stuff that doesn’t look anything like rooms or table tops or sheets of paper. These are spaces built of things like functions, or of sets of things, or of ways to manipulate things. Spaces built of the ways you can subdivide the integers. The details vary. But there’s something in common in all these ideas that communicates.

Mark Anderson’s Andertoons for the 11th is the Mark Anderson’s Andertoons for the week. I think we’ve all seen this joke go across our social media feed and it’s reassuring to know Mark Anderson has social media too. We do talk about solving for x, using the language of describing how we help someone get past a problem. I wonder if people might like this kind of algebra more if we talked more about finding out what values ‘x’ could have that make the equation true. Well, it won’t stop people feeling they don’t like the mathematics they learned in school. But it might help people feel like they know why they’re doing it.

You can see this and more essays about comic strips by following this link. Other essays describing The Argyle Sweater are at this link. Essays inspired by Frank and Ernest are at this link. And some of the very many essays about Andertoons are at this link. Enjoy responsibly.

## Who We Just Know Is Not The Most Improved Pinball Player

Back before suddenly everything got complicated I was working on the question of who’s the most improved pinball player? This was specifically for our local league. The league meets, normally, twice a month for a four-month season. Everyone plays the same five pinball tables for the night. They get league points for each of the five tables. The points are based on how many of their fellow players their score on that table beat that night. (Most leagues don’t keep standings this way. It’s one that harmonizes well with the vengue and the league’s history.) The highest score on a game earns its player 100 league points. Second-highest earns its scorer 99 league points. Third-highest earns 98, and so on. Setting the highest score to a 100 and counting down makes the race for the top less dependent on how many people show up each night. A fantastic night when 20 people attended is as good as a fantastic night when only 12 could make it out.

Last season had a large number of new players join the league. The natural question this inspired was, who was most improved? One answer is to use linear regression. That is, look at the scores each player had each of the eight nights of the season. This will be a bunch of points — eight, in this league’s case — with x-coordinates from 1 through 8 and y-coordinates from between about 400 to 500. There is some straight line which comes the nearest to describing each player’s performance that a straight line possibly can. Finding that straight line is the “linear regression”.

A straight line has a slope. This describes stuff about the x- and y-coordinates that match points on the line. Particularly, if you start from a point on the line, and change the x-coordinate a tiny bit, how much does the y-coordinate change? A positive slope means the y-coordinate changes as the x-coordinate changes. So a positive slope implies that each successive league night (increase in the x-coordinate) we expect an increase in the nightly score (the y-coordinate).

For me, I had a slope of about 2.48. That’s a positive number, so apparently I was on average getting better all season. Good to know. And with the data on each player and their nightly scores on hand, it was easy to calculate the slopes of all their performances. This is because I did not do it. I had the computer do it. Finding the slopes of these linear regressions is not hard; it’s just tedious. It takes these multiplications and additions and divisions and you know? This is what we have computing machines for. Setting up the problem and interpreting the results is what we have people for.

And with that work done we found the most improved player in the league was … ah-huh. No, that’s not right. The person with the highest slope, T, finished the season a quite good player, yes. Thing is he started the season that way too. He’d been playing pinball for years. Playing competitively very well, too, at least when he could. Work often kept him away from chances. Now that he’s retired, he’s a plausible candidate to make the state championship contest, even if his winning would be rather a surprise. Still. It’s possible he improved over the course of our eight meetings. But more than everyone else in the league, including people who came in as complete novices and finished as competent players?

So what happened?

T joined the league late, is what happened. After the first week. So he was proleptically scored at the bottom of the league that first meeting. He also had to miss one of the league’s first several meetings after joining. The result is that he had two boat-anchor scores in the first half of the season, and then basically middle-to-good scores for the latter half. Numerically, yeah, T started the season lousy and ended great. That’s improvement. Improved the standings by about 6.79 points per league meeting, by this standard. That’s just not so.

This approach for measuring how a competitor improved is flawed. But then every scheme for measuring things is flawed. Anything actually interesting is complicated and multifaceted; measurements of it are, at least, a couple of discrete values. We hope that this tiny measurement can tell us something about a complicated system. To do that, we have to understand in what ways we know the measurements to be flawed.

So treating a missed night as a bottomed-out score is bad. Also the bottomed-out scores are a bit flaky. If you miss a night when ten people were at league, you get a score of 450. Miss a night when twenty people were at league, you get a score of 400. It’s daft to get fifty points for something that doesn’t reflect anything you did except spread false information about what day league was.

Still, this is something we can compensate for. We can re-run the linear regression, for example, taking out the scores that represent missed nights. This done, T’s slope drops to 2.57. Still quite the improvement. T was getting used to the games, apparently. But it’s no longer a slope that dominates the league while feeling illogical. I’m not happy with this decision, though, not least because the same change for me drops my slope to -0.50. That is, that I got appreciably worse over the season. But that’s sentiment. Someone looking at the plot of my scores, that anomalous second week aside, would probably say that yeah, my scores were probably dropping night-to-night. Ouch.

Or does it drop to -0.50? If we count league nights as the x-coordinate and league points as the y-coordinate, then yeah, omitting night two altogether gives me a slope of -0.50. What if the x-coordinate is instead the number of league nights I’ve been to, to get to that score? That is, if for night 2 I record, not a blank score, but the 472 points I got on league night number three? And for night 3 I record the 473 I got on league night number four? If I count by my improvement over the seven nights I played? … Then my slope is -0.68. I got worse even faster. I had a poor last night, and a lousy league night number six. They sank me.

And what if we pretend that for night two I got an average-for-me score? There are a couple kinds of averages, yes. The arithmetic mean for my other nights was a score of 468.57. The arithmetic mean is what normal people intend when they say average. Fill that in as a provisional night two score. My weekly decline in standing itself declines, to only -0.41. The other average that anyone might find convincing is my median score. For the rest of the season that was 472; I put in as many scores lower than that as I did higher. Using this average makes my decline worse again. Then my slope is -0.62.

You see where I’m getting more dissatisfied. What was my performance like over the season? Depending on how you address how to handle a missed night, I either got noticeably better, with a slope of 2.48. Or I got noticeably worse, with a slope of -0.68. Or maybe -0.61. Or I got modestly worse, with a slope of -0.41.

There’s something unsatisfying with a study of some data if handling one or two bad entries throws our answers this far off. More thought is needed. I’ll come back to this, but I mean to write this next essay right away so that I actually do.

## Reading the Comics, August 8, 2018: Hm Edition

There are times I feel like my writing here collapses entirely to Reading the Comics posts. It’s a temptation to just give up doing anything else. They’re easy to write, since the comics give me the subjects to discuss. And it offers a nice, accessible mix of same-old topics with the occasional oddball. It’s fun. But sometimes Comic Strip Master Command decides I’ve been doing enough of that. This is one of those weeks; I only found six comics in my normal reading that were on point enough to discuss. So here’s half of them.

Bill Rechin’s Crock for the 6th is … hm. Well, let’s call it a fractions joke. I’m curious exactly what the clerk’s joke is supposed to mean. Is it intended to suggest an impossibility, putting into something far more than it can hold? Or is it just meant to suggest gross overabundance? And deep down I suspect Rechin didn’t have any specific meaning; it’s just a good-sounding insult.

Hector D Cantu and Carlos Castellanos’s Baldo for the 7th is … hm. Well, let’s call it a wordplay joke. It works by “strength” having multiple meanings, and “numbers” having multiple meanings. And there being a convenient saying to link one to the other. If this were a busier week I wouldn’t even bring it up, but I hate going without anything around here.

Keith Tutt and Daniel Saunders’s Lard’s World Peace Tips for the 8th is … hm. Well, let’s call it a Roman numerals joke. It’s really more wordplay. And one I like, although the pacing is off. The second panel could be usefully dropped, and you could probably redo this all in two panels — or one — to better effect.

They’ve been phasing Roman Numerals out for a long while. Arabic numerals got their grand introduction to the (Western) Roman Empire’s territories in 1202 by Leonardo of Pisa, known now as “Fibonacci”. His Liber Abaci (Book of Calculation) laid out the Arabic numerals scheme and place values, and how to use them. By 1228 he published an edition comparing Roman numerals to Arabic numerals.

This wasn’t the first anyone in western Europe had heard of them, mind. (It never is; anyone telling you anything was the first is simplifying.) Spanish monks in the 10th century studied Arabic texts, and wrote about what they found. But after Leonardo of Pisa, Arabic numerals started displacing Roman numerals at least in specialized trades. Florence, in what is now Italy, prohibited merchants from using Arabic numerals in 1299; they could use Roman numerals or write them out in words. This, presumably, to prevent cheating by use of strange, unfamiliar calculus. Arabic numerals escaped being tools of specialists in the 16th century, thanks in large part to the German mathematician Adam Ries, who explained the scheme in terms apprentices could understand.

Still, these days, a Roman numeral is mostly an affectation. Useful for bit of style; not for serious mathematics. Good for watches.

Well. I keep all my Reading the Comics essays tagged so that you can read them at this link. Other essays that mention Crock should be available at this link. If you’re more interested in Baldo other essays mentioning it should be here. And other Lard’s World Peace Tips, when they inspire mathematical thoughts, are available at this link. Thank you.