Mathematician. Reader. Fiftysomething. Cruciverbalist. Not very good at thinking of witty things to put in short bios.

I wasn't on Twitter before that nice Mr Musk suggested that everyone go to Mastodon, and I don't expect to be very active here, but who knows?

Last Notes

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Au contraire, it's definitely rouge.

2026-02-10 22:38:19 UTC

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Are you sure about your Juliuses and your Scaligers?
It looks to me as if:
Julius Caesar (the emperor) introduced the Julian calendar.
Julius Caesar Scaliger was an erudite chap but had nothing much to do with calendars.
Joseph Justus Scaliger, Julius Scaliger's son, introduced the "Julian period" and (kinda) the "Julian day number".
The "Julian" there is a reference to the Julian calendar, _not_ to his dad.
... But I am not an expert, I'm just reporting what I find in Wikipedia, and maybe the above is all wrong?

2026-01-20 20:40:07 UTC

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I suspect DLL's comment is a deliberate reference to this, but in case (1) it isn't or (2) others didn't notice, Raymond Smullyan wrote a whole book with this premise: https://en.wikipedia.org/wiki/To_Mock_a_Mockingbird

2025-10-09 14:47:54 UTC

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By "fairly small" I meant on the order of 10^-10, which is the sort of thing I would expect to be fairly easily achievable in multiple ways by things looking like linear combinations of spherical shells.

2025-10-09 12:49:30 UTC

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Note that the gravitational field of _any_ spherically-symmetrical thing is the same (up to a scaling of the total mass) _everywhere_ outside the sphere containing it. So it doesn't particularly matter whether the sample points are all on a single sphere.
Of course, that's what's true for an _actually literally spherically symmetrical_ mass density, and what you've got here is just an approximation to that. I don't think I'd have predicted ahead of time that the determinant would be so very small ... though maybe what's going on isn't that there are _incredibly small eigenvectors_ but that there are _quite a lot of fairly small eigenvectors_.
Further conjecture: if you move your sample points further out, the determinant will get smaller; if you move them further in, it will get larger. (On the grounds that I expect the spherically-symmetrical approximation to get better at larger distances.)

2025-10-09 12:22:50 UTC

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Have you looked to see what the almost-nullspace looks like? That is, what not-very-short vectors are mapped almost-to-zero? Or, to put it differently: your empirical finding shows that some distributions of mass have almost the same effect on your 83 red dots as others; what are they?
My best guess, which I don't trust much: your 83 red dots are all at a single distance, so any distribution of mass that looks "enough" like a spherical shell of any size smaller than that will look (up to scaling the masses) exactly like any other, and perhaps your nearly-nullspace vectors look like linear combinations of spherical shells.

2025-09-02 11:48:27 UTC

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It's too bad it can't be A000001. Though it wouldn't by any means be the first known-to-be-finite OEIS sequence; for instance A100000 is another.

2025-08-22 12:48:25 UTC

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Some years ago, in the UK there was an election which the Liberal Democrat candidate was expected to win, with the Conservative candidate a close second. So the Conservatives got someone to run as a "Literal Democrat", he picked up a bunch of votes from people who didn't read carefully, and the Conservatives won. (The election regulations got changed after that so we didn't get the otherwise-inevitable deluge of "Conversatives" and "Literal Democrats" fighting to see who could confuse more voters.)
Are these people hoping to attract parents who think they're getting a Montessori school? It seems kinda unlikely, so I guess they either don't know or don't care about the similarity in name. Neither is very encouraging.

2025-08-06 14:15:16 UTC

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By a curious coincidence, RFK Jr. _is_ an evil troll whose actions are likely to make some children sneeze non-stop until they drop dead, or at least something in the same conceptual vicinity.

2025-08-02 18:38:45 UTC

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I hope they made it not too difficult for people to leave early. I'm going to guess you weren't the only ones.

2025-08-02 12:26:50 UTC

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Good luck! (I like Tavener but I don't think I would cope well with 8 hours of one Tavener piece at a stretch.)

2025-08-02 10:30:57 UTC

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Pedantic note: I think you mean not "The Protecting Veil", a famous Tavener piece but only ~45 minutes long, but "The Veil of the Temple", a newer piece by the same composer that is, indeed, 8 hours long.

2025-07-22 00:04:07 UTC

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This is a slightly atypical case because usually when something's named after X it's because someone else discovered the thing first and then X wrote about it later[1], whereas in this case IIUC Moessner really did get there first but didn't _prove_ it.
[1] Though my actual favourite example is Pell's equation, which so far as I can tell Pell never worked on _at all_.

2025-06-15 13:21:05 UTC

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That paper also contains the line "the d-ism of Leibniz overtook the dotage of Newton" which is rather magnificent. Knuth puts it in quotes but doesn't say who it's from; it seems to be Charles Babbage, though his wording was a little different.

2024-12-02 21:18:59 UTC

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Whether or not _that_ was a joke, there's something very appropriate about your photo showing Aristote's Fragme Sele.

2024-10-20 15:05:25 UTC

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You don't have to expend time or money getting to and from the movie theatre. You have comfier seating. If you have friends or family, you can all watch at once for the same price. You are much less likely to catch whatever infectious diseases may be going around.
How all of that weighs against the larger screen, the maybe-better sound system, the appeal of the traditional movie-theatre atmosphere, etc., will vary from person to person. But I'm betting they wouldn't be setting their prices at 150% of cinema ticket prices if there weren't plenty of people for whom watching at home is a significantly better experience.