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Timeline for Trichotomies in mathematics

Current License: CC BY-SA 4.0

96 events
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Oct 4 at 23:30 history edited LSpice CC BY-SA 4.0
Tidying and links, while this is on the front page
Oct 4 at 19:55 history edited ThiKu CC BY-SA 4.0
edited body
Oct 4 at 19:20 answer added Joshua Grochow timeline score: 0
Aug 7, 2023 at 6:37 comment added Pietro Majer (On a side note, I've always found a bit funny the word "trichotomy", that should also mean "hair cutting")
Aug 7, 2023 at 6:00 answer added José Hdz. Stgo. timeline score: 1
Apr 6, 2019 at 15:59 comment added user137767 $\mathrm{Spec}\, \mathbb{Z}$ is not the analogue of $S^3$. You have to compactify at archimedean place, otherwise it is a punctured sphere (whose homotopy type is very different)
Dec 30, 2017 at 15:20 review Close votes
Dec 30, 2017 at 23:05
Jun 26, 2017 at 17:54 answer added user56097 timeline score: 3
Apr 13, 2017 at 12:58 history edited CommunityBot
replaced http://mathoverflow.net/ with https://mathoverflow.net/
Apr 21, 2016 at 13:33 answer added Sean Lawton timeline score: 4
Mar 17, 2015 at 13:08 answer added Steve Huntsman timeline score: 4
Nov 7, 2014 at 5:09 answer added Gerry Myerson timeline score: 14
Feb 13, 2013 at 9:42 answer added shane.orourke timeline score: 3
Feb 13, 2013 at 6:47 answer added LeBlanc timeline score: 6
Feb 11, 2013 at 17:07 answer added Alexander Chervov timeline score: 14
Feb 9, 2013 at 7:57 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 9, 2013 at 5:43 comment added user30304 mathoverflow.net/questions/22927/…
Feb 9, 2013 at 5:41 comment added user30304 mathoverflow.net/questions/13029/…
Feb 9, 2013 at 5:40 comment added user30304 mathoverflow.net/questions/40178/freshmans-definition-of-sinx/…
Feb 8, 2013 at 21:53 history reopened Gil Kalai
Alexander Chervov
Todd Trimble
Gjergji Zaimi
Benjamin Steinberg
Feb 8, 2013 at 21:46 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 8, 2013 at 17:48 comment added user30304 For a Riemannian signature Einstein AH structure on a compact n-manifold there holds one of the following mutually exclusive possiblities: 1) It is proper and exact with parallel scalar curvature. 2) Its scalar curvature is identically zero and it is closed. 3) It is not closed, and its scalar curvature is not parallel. arxiv.org/pdf/1203.2575
Feb 8, 2013 at 17:43 comment added user30304 Structure of Kac–Moody algebras: finite type, affine type, and wild type.
Feb 8, 2013 at 17:06 comment added user30304 Tautology/contingency/absurdity for propositional forms and the analogous valid/satisfiable/unsatisfiable. books.google.com/books?id=t5r79vZ9ogoC&pg=PA75
Feb 8, 2013 at 17:04 comment added user30304 An infinite locally finte homogenneous geometry is isomorphic to 1) trivial geometry, 2) projective geometry over a finite field, or 3) affine geometry over a finite field. books.google.com/books?id=8NTWRFD5lZ8C&pg=PA367
Feb 8, 2013 at 16:16 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 7, 2013 at 17:14 comment added Emil Jeřábek The natural classification of theories based on their stability spectrum is not a trichotomy, but a tetrachotomy (unstable, strictly stable, strictly superstable, totally transcendental), reinforcing the argument that this question is rather arbitrary.
Feb 7, 2013 at 17:10 comment added Jonathan Beardsley Perhaps more interesting would be investigating a function whose value at $n$ is "the number of interesting examples of $n$-chotomies in mathematics" as I suspect it would decrease rather quickly. However, philosophically, there is a probably a good reason that there are many examples of dichotomies and trichotomies, as opposed to, say 11-chotomies. Perhaps this is connected to the relative smallness of the human mind, in some sense. Additionally though, such a philosophical argument would show that such a question is pretty silly.
Feb 7, 2013 at 16:47 comment added Gil Kalai There was a somewhat related discussion on "trialities" (The 3-analog of "dualities") over the n-category cafe here golem.ph.utexas.edu/category/2007/01/…
Feb 7, 2013 at 16:41 history edited Gil Kalai CC BY-SA 3.0
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Feb 7, 2013 at 16:22 comment added Gil Kalai There is an important trichotomy in model theory between super-stable theories, strict-stable (stable but not superstable) theories, and non stable theories. (There are other important trichotomies in model theory and set theory.)
Feb 7, 2013 at 6:09 history closed Gerald Edgar
Franz Lemmermeyer
Dan Petersen
Misha
Chandan Singh Dalawat
no longer relevant
Feb 6, 2013 at 21:05 answer added Axel Boldt timeline score: 21
Feb 6, 2013 at 18:46 answer added Lee Mosher timeline score: 11
Feb 6, 2013 at 18:40 comment added Todd Trimble Ah, excellent Terry. I have just posted an answer based on this.
Feb 6, 2013 at 18:39 answer added Todd Trimble timeline score: 4
Feb 6, 2013 at 17:50 comment added Terry Tao Analogously: a natural number is either a unit, a prime, or a composite.
Feb 6, 2013 at 16:13 comment added Todd Trimble Oh hey, here's one from another recent thread (see Terry Tao's comment here: mathoverflow.net/questions/120536/is-the-empty-graph-a-tree/…): a space is either unconnected, connected, or disconnected. :-)
Feb 6, 2013 at 8:16 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 5, 2013 at 16:57 comment added user9072 @Franz Lemmermeyer: A simple reason can be that a user cannot yet upvote ;D Actaully subtracting these two, and accounting for the fact that two other users have two answers (visible) we arive at 21=21. Not taking potentially downvotes into account. But likely it is true not everybody answering upvoted, in general I see no problem with this. (I upvote things I find good and answer as long I find it acceptable [and am able to]. Seems reasonable to me.)
Feb 5, 2013 at 16:01 comment added Franz Lemmermeyer MO is becoming more and more ridiculous. I don't even understand why people bother answering questions they do not even think worthy of upvoting.
Feb 5, 2013 at 10:11 history edited Qfwfq CC BY-SA 3.0
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Feb 5, 2013 at 9:16 history edited Ryan Budney
add tags
Feb 5, 2013 at 0:08 answer added André Henriques timeline score: 16
Feb 4, 2013 at 23:17 history reopened Jonah Sinick
GH from MO
user9072
Asaf Karagila
Vesselin Dimitrov
Feb 4, 2013 at 22:02 comment added GH from MO I think this question is a good one, because it generates interesting answers.
Feb 4, 2013 at 20:46 history closed Tom Goodwillie
Eric Wofsey
HJRW
David White
Felipe Voloch
not a real question
Feb 4, 2013 at 19:16 comment added Todd Trimble Do I understand correctly, unknown (yahoo), that your comments are meant to undermine the question so that it gets closed? If so, then I get it. And if so, please cut it out already.
Feb 4, 2013 at 17:54 comment added user30304 Underdetermined, determined, overdetermined.
Feb 4, 2013 at 16:36 comment added David White Meta thread here: tea.mathoverflow.net/discussion/1525/…. Please upvote this comment so it appears "above the fold"
Feb 4, 2013 at 14:26 comment added user30304 SubX, X, superX.
Feb 4, 2013 at 14:24 comment added user30304 Clockwise, anti-clockwise, stationary.
Feb 4, 2013 at 14:23 comment added user30304 One, both, neither.
Feb 4, 2013 at 14:23 comment added user30304 Win , loss, draw.
Feb 4, 2013 at 12:29 answer added user30304 timeline score: 13
Feb 4, 2013 at 10:33 answer added Guy R. timeline score: 3
Feb 4, 2013 at 10:16 answer added A. Bellmunt timeline score: 11
Feb 4, 2013 at 10:13 answer added David Corwin timeline score: 8
Feb 4, 2013 at 10:11 comment added David Corwin In American History class, we had this theory that every single war came in three stages, and it seemed to hold up pretty well...
Feb 4, 2013 at 8:03 answer added GH from MO timeline score: 37
Feb 4, 2013 at 2:29 comment added Todd Trimble Let's please not be quick to close this question. There are some intriguing clusters of answers, some along a (negative, 0, positive) axis, and others along a (closed, open, closed) axis [if I may put it crudely], and others along other axes still. There is a certain amount of erudition in both the question and answers, and there is some potential to glimpse "analogies between analogies" in the words of Ulam. It could be a useful exercise to pursue this.
Feb 4, 2013 at 1:13 comment added user30304 There are three eras of mathematics: 1) mathematics, 2) relatively new mathematics, 3) emerging mathematics. Anything between Poincaré and recently is designated as "relatively new". Anything in last couple of decades is termed "emerging".
Feb 4, 2013 at 0:31 comment added user30304 There are three types of people. Those that can count. And those that can't.
Feb 3, 2013 at 15:12 answer added Lee Mosher timeline score: 11
Feb 3, 2013 at 14:32 answer added Asaf Karagila timeline score: 30
Feb 3, 2013 at 14:17 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 13:49 answer added Andrea Mori timeline score: 3
Feb 3, 2013 at 13:45 comment added Andrea Mori Holy Trinity! That's a striking observation.
Feb 3, 2013 at 13:28 comment added Eric Wofsey This feels like an awfully arbitrary and contentless question to me. This seems like asking, what are some interesting sets with 3 elements? Voting to close. A more reasonable question would be to ask for examples where there is an interesting hyperbolic-parabolic-elliptic trichotomy and connections between these examples.
Feb 3, 2013 at 13:28 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 13:21 answer added Joe Silverman timeline score: 10
Feb 3, 2013 at 11:11 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 10:05 comment added Benjamin Dickman From the movie $\pi$: "Hold on. You have to slow down. You're losing it. You have to take a breath. Listen to yourself. You're connecting a computer bug I had with a computer bug you might have had and some religious hogwash. You want to find the number 216 in the world, you will be able to find it everywhere. 216 steps from a mere street corner to your front door. 216 seconds you spend riding on the elevator. When your mind becomes obsessed with anything, you will filter everything else out and find that thing everywhere."
Feb 3, 2013 at 9:49 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 9:10 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 9:04 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 8:01 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 7:49 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 3, 2013 at 5:31 answer added Sam Lewallen timeline score: 26
Feb 3, 2013 at 3:44 answer added Koushik timeline score: 1
Feb 3, 2013 at 3:03 answer added Terry Tao timeline score: 19
Feb 3, 2013 at 2:13 answer added Harry Altman timeline score: 5
Feb 3, 2013 at 0:52 answer added Michael Joyce timeline score: 2
Feb 2, 2013 at 22:14 answer added Alexandre Eremenko timeline score: 47
Feb 2, 2013 at 21:41 answer added Vaughn Climenhaga timeline score: 7
Feb 2, 2013 at 21:38 answer added Simon Lyons timeline score: 5
Feb 2, 2013 at 21:24 answer added Paul Reynolds timeline score: 17
Feb 2, 2013 at 21:18 answer added shane.orourke timeline score: 11
Feb 2, 2013 at 21:14 comment added user5117 A finitely-generated infinite group has 1, 2, or infinitely many ends. (But if you leave out the word "infinite", it becomes a tetrachotomy; this seems to be a weakness of the question.)
Feb 2, 2013 at 21:09 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 2, 2013 at 21:02 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 2, 2013 at 20:59 answer added Mariano Suárez-Álvarez timeline score: 8
Feb 2, 2013 at 20:51 answer added Mariano Suárez-Álvarez timeline score: 19
Feb 2, 2013 at 20:46 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 2, 2013 at 20:32 history edited Vesselin Dimitrov CC BY-SA 3.0
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Feb 2, 2013 at 20:25 history asked Vesselin Dimitrov CC BY-SA 3.0