Alon Amit
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 Sep 29 awarded Yearling Jul 27 revised Point sets in Euclidean space with a small number of distinct distances Fixed exponent of n to 77/141. Jul 24 awarded Nice Answer Jul 7 awarded Nice Answer Sep 30 awarded Yearling Sep 19 revised Number of finite simple groups of given order is at most 2 - is a classification-free proof possible? Added a few LaTeX tags. Sep 19 comment out-trees and least upper boundness I'm still very confused. Yes, lattices contain semicycles, that's just the point - you were asking if every LUB graph is a (kind of) tree, and it isn't. You now changed the question to ask if every connected digraph without semicycles (which further satisfies LUB) must be a (kind of) tree. Well, it is, by definition, right? The underlying undirected graph certainly is a tree (connected and cycle free). This is just an out-tree except that we haven't chosen a specific root. Sep 16 comment Finite simple groups and conjugacy classes with 2p elements Is it known that this can't occur with the alternating groups? Empirically it looks like the sizes of the conjugacy classes of $A_n$ all have at least 3 prime factors once $n>8$. Sep 16 comment Spanning trees in 3 regular graphs. What do "clip" and "half edges" mean? Sep 15 answered out-trees and least upper boundness Sep 11 comment Second eigenvalue of suspension of a graph Shouldn't you be looking at the Laplacian, rather than the adjacency matrix? For non-regular graphs I'm not sure if the second largest eigenvalue is the thing that controls mixing. Also, the operation you're interested in seems more like taking the cone over $G$, rather than a suspension. Sep 2 revised Do good math jokes exist? Fixed broken YouTube link. Aug 26 revised Theorems for nothing (and the proofs for free) typo correction. Aug 5 comment What are some proofs of Godel's Theorem which are *essentially different* from the original proof? An awesome summary! Jul 28 revised Maximal ideals in the ring of continuous real-valued functions on R LaTeXification. Jul 28 comment What should be learned in an introductory analytic number theory course? I'm curious: what is "Pollack's new book"? Jun 18 comment Gently falling functions Sorry if that's a silly question but in example 1), a particle starting at (0,1) won't go anywhere unless you give it some initial horizontal velocity. Are you suggesting that the separation point tends to the indicated point as that velocity tends to 0? Jun 17 comment Proof that any NP problem can be reduced (in P time) to any problem in NPC? I don't understand your modified question. Of course every problem in NP can be reduced some subset of NP problems - it can be "reduced" to itself, and often to lots of other problems polynomially-equivalent to it. Why does that imply that NPC is empty? Jun 11 comment Is there any sequence $a_n$ of nonnegative numbers for which $\sum_{n \geq 1}a_n^2 <\infty$ and $\sum_{n \geq 1}\left(\sum_{k \geq 1}\frac{a_{kn}}{k}\right)^2=\infty$? In line 3, did you mean "the sequence whose $n$-th term is..."? Jun 3 comment Examples of theorems misapplied to non-mathematical contexts If he does, it's a slam dunk.