Category Archives: Math

Terrible notation Hall of Fame

This one is a little harder to explain than my earlier post. Your attention should be focused on the line in the middle that begins “N(T) = …” and ends with a diamond. That line contains three copies of the … Continue reading

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How not to do voting theory

This WaPo op-ed (by Edward Foley and Eric Maskin) is so, so bad that I’m still upset about it two days later. They criticize Alaska’s instant runoff election system because it doesn’t meet the Condorcet criterion: Pelota won, even though … Continue reading


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Terrible calculus answers Hall of Fame

What is so beautiful about this is that even if you don’t have any idea what a derivative is, how to compute one, or what the pictures mean, it is still completely clear how bad this answer is.

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This is so sad

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The big point theorem

The solution Tanya attributes to Jason Rosenhouse here reminds me of my favorite theorem of applied mathematics education: Theorem (Big Point Theorem). Any three lines are concurrent, provided you draw the point big enough. Edit 8/18: And now Tanya has … Continue reading

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Map of the world

At least as far as families of reflection groups with nice combinatorics are concerned

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Ikea proofs

Overheard: He writes a lot of Ikea proofs — all the parts are there,but the reader has to assemble them, and sometimes there are a fewextra parts at the end.

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“Magical Mathematics” by Persi Diaconis and Ron Graham

This was a gift from my wonderful friend AHM, following the death of Graham last year. I enjoyed it quite a lot, but it’s also very weird. For example, chapters bounce around dramatically in tone and content (some are about … Continue reading

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“Mathematical education” by G. St. L. Carson

This is the other book I mentioned finding at the Book Barn.  It is a collection of eight lectures delivered by the author in 1912 and 1913, and a fascinating historical document.  Some features that I found particularly interesting follow. … Continue reading

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Trapezoids, and blogs

Atrios remarked on the (slow, in-progress) death of the open internet, as in blogs etc. And Jonathan’s offhand remark about his blog’s heyday is another anecdatum pointing in the same direction. Anyhow, that’s not what this post is about; it’s … Continue reading

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