Mark Dominus / is on Nostr

I am an amateur mathematician, but not the angle-trisecting kind.

Last Notes

2024-08-08 16:19:28

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@npub1upk…tcwy Command-line editing is messed up because the shell is confused about terminal width or terminal capabilities or the length of the prompt or something like that

2024-08-02 12:43:20

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@npub1c9m…9xjd This led me to wonder about fixed points of the Fourier transform. I suppose you know all about this, but it was news to me and I spent quite a while down a lovely rabbit hole of Hermite functions.
Thank you!

2024-05-24 22:52:30

This is the world's first use of the modern equals sign, from Robert Recorde's 1557 book _The Whetstone of Witte_.
(Screencap from Internet Archive's scan of the book: https://archive.org/details/TheWhetstoneOfWitte/page/n237/mode/2up)
(I also wrote a blog post a couple of years back explaining what it says if you are interested: https://blog.plover.com/math/recorde.html)
https://media.mathstodon.xyz/media_attachments/files/112/498/026/431/331/805/original/158c32b11eece353.png

2024-04-22 18:19:13

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@npub1c9m…9xjd Is it perhaps when a group of people throws someone in the air, then catches them again, repeatedly?

2024-04-22 18:11:34

All numbers are finite, but some numbers are more finite than others.

2024-04-21 19:08:19

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@npub1c9m…9xjd no problem, your statement was sufficiently helpful

2024-04-21 18:25:42

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@npub1c9m…9xjd The bit I was missing is that the inverses are also matrices over Z.
Thanks!

2024-04-21 18:10:55

What does SL(2, Z) mean? Z isn't a field, and the matrices over Z don't form a group.

2024-04-18 21:21:38

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@npub1upk…tcwy I feel pretty much the same way, but all the same I'm eagerly hoping that whatever replaces it will be better.

2024-04-07 22:46:25

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@npub1knz…c73p It's interesting that it starts at M in the middle and follows the circle of fifths downwards. A Western version would most likely have gone in the reverse order.

2024-03-13 14:42:52

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@npub1upk…tcwy hey, I thought of one that might be (b) but might be different: it was designed to work under resource constraints that made sense historically but that no longer apply (and may be forgotten).
Examples:
1. Horrible sendmail.cf syntax was designed to be parsred very quickly on slow 1970's hardware with not-fully-developed-yet 1970's parsing technology.
2. C90 standard requires that externally-visible identifiers (e.g. library functions like printf and malloc) must have nanes that are all unique in the first 6 characters, for compatibility with then-existing linkers that ran in highly memory-constrained environments.

2024-02-16 21:26:27

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@npub1upk…tcwy I don't know, but I looked a little. The string `HEAD` (upper case) does not appear in the Monotone docs. “current heads” appears once, “current head” not at all. I couldn't find the Monotone jargon for “the branch I have checked out in the current workspace”.
But I think it seems clear that Monotone is the source of the name of `.git/refs/heads`.

2024-02-16 21:09:42

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@npub1upk…tcwy I was going to reply that you should check the Monotone docs. Git was stongly influenced by Monotone (and not at all by CVS / SVN, which Linus despised.) So a plausible answer to any question of the form “Where does Git get this terminology” is “Maybe from Monotone?” And I think that does seem to be the case here. https://www.monotone.ca/docs/Branches.html#Heads-and-merging

2024-02-05 19:24:38

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@npub1upk…tcwy I have a problem similar to #3 also, except my problem seems to be that stash _does_ promise to stash the index and the working tree separately, but then it usually doesn't restore them properly. I'm not sure what the underlying issue is and I haven't made time to look into it.

2023-12-19 15:14:25

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@npub1upk…tcwy I've always been baffled that GNU didn't lean heavily into an Info to HTML converter when web browsers started to become common, around 1995. It seems to me that the completely dropped the ball there.
Like everyone else, I didn't want to use the awful info browser they supplied.
But what if those stub man pages had said “or visit http://www.gnu.org/info/emacs/ for full details"? Then maybe something would have happened?

2023-11-21 14:39:33

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@npub1upk…tcwy I was going to dispute that, because _technically_ the two sides are symmetric, but on a little reflection I realized you were right—that _is_ how we think of it and talk about it.
Previously I think I would have said that the `main` and `branch` branches in your picture share commits. But I think your description is closer to the way people usually think about it. Rebasing `branch` onto `main` would be routine. Rebasing `main` onto `branch` would be super-weird.