Reputation
34,590
Next tag badge:
1366/1000 score
173/200 answers
Badges
4 119 207
Newest
 Nice Answer
Impact
~942k people reached

6h
comment Is this group given presentation isomorphic to $\mathbb{Z}_2$, and why?
Samarkand, I think it would be much better if you would ask the second question (about random group presentations) in a separate post, since it's an entirely different question. This would also give you an opportunity to sharpen the question: think about which probability measure would be the most meaningful to you and why, rather than leave the choice to the reader. (Just a suggestion.) I agree with YCor that the first question is substantial enough to stand on its own, and that it should not be migrated.
16h
revised Is this group given presentation isomorphic to $\mathbb{Z}_2$, and why?
reverted title and amended the question
16h
comment Is this group given presentation isomorphic to $\mathbb{Z}_2$, and why?
It's probably not a good idea to alter the question after receiving an answer, in a way that makes the answer no longer relevant. I'm going to revert the tltle and change the body slightly so that Francesco's answer is still relevant.
18h
comment Mixed integer programming formulation for Ising model
I'm voting to close this question as off-topic because it was cross-posted and answered at another site.
1d
comment similarity measure (characteristics vector) from discrete lattice system to continuous
I'm voting to close this question as off-topic because of multiple crosspostings.
1d
comment machine learning representations of infinite number of periodic points on a 3D space
I'm voting to close this question as off-topic because of multiple crosspostings.
1d
comment What is the number of self-inverse permutations on a set of cardinality $N$?
Oh, by the way: "self-inverse" is fine, but I think it's more common to call such permutations involutions.
1d
comment What is the number of self-inverse permutations on a set of cardinality $N$?
No, I don't think you should delete the question (actually you can't self-delete since one answer has been upvoted). One reason it's frowned upon is because it may make it appear the question is not meant as a 'real question'. This may be a peculiarity with 'MO culture' as you say, and there is nothing 'illegal' about it.
1d
comment What is the number of self-inverse permutations on a set of cardinality $N$?
Posting a question you already knew the answer to is frowned upon here.
2d
comment irrationality of the p-adic exponential
@FedorPetrov Yes, that's the sole exception, but an exception it is.
2d
comment Generalizing Ramanujan's “1729 story”
I don't know that it was off the top of his head. There is classical number theory (involving Gaussian primes) about the number of ways of a number can be represented as the sum of two squares, and it wouldn't be unnatural to try to investigate the situation about sums of two cubes, so maybe it's just something he happened to know from past investigations.
2d
comment What's the probability distribution of a deterministic signal or how to marginalize dynamical systems? (functional integrals in probability theory)
Got your messages, Fabrice.
Apr
26
comment Mathematicians with Aphantasia (Inability to Visualize Things in One's Mind)
It will be a sense of the room that doesn't have much to do with perspective. It's hard -- that is, it takes a lot of training -- to go from a spatial image to a picture on paper. So these things are not necessarily stored in our minds in a visual sort of way. We translate what we see into a sense of space. If you think of it, you realize that if you imagine a table with four chairs around it, it doesn't matter whether you can see the seats of the chairs. You just know that they are there. It's kinesthetic as well as visual." MurphyKate, does this at all correlate with your experience?
Apr
26
comment Mathematicians with Aphantasia (Inability to Visualize Things in One's Mind)
Here is Bill Thurston on the example of the blind mathematician Morin and his work on sphere eversion (More Mathematical People, pp. 337-338): "It's something most people have a great deal of trouble visualizing. In fact, I think that vision is somehow distracting to the spatial sense, because we have a spatial sense that is more than just vision. People associate it with vision, but it's not the same. If I close my eyes and imagine what this room is like, I will have a sense in my mind that there's a table here and something here and there. (cont.)
Apr
26
comment Probability theory without deductive closure
Paul's comment certainly discourages expressing a dissenting opinion, so to avoid getting into an argument, the downvoter may well feel it would be wiser to keep his/her mouth shut. And that's too bad.
Apr
25
comment Nelson's proof of Liouville's theorem
Belongs in Proofs from THE BOOK. Lucid, beautiful, unforgettable.
Apr
25
awarded  Nice Answer
Apr
23
comment What's the probability distribution of a deterministic signal or how to marginalize dynamical systems? (functional integrals in probability theory)
Keep in mind that the notification system doesn't work if there's a space between @ and the user name. (Your last comment should have gotten through though.)
Apr
21
comment Two questions on Elias Stein paper (1976)
@TerryTao (and/or Mark Lewko): do you have a good idea which paper(s) the OP is referring to (in the versions of the question before the edit by Leitão)? I suppose an answer to that would also answer the question of whom he is addressing.
Apr
21
revised Proof of a fact about traces
rolled back to a previous revision