bio | website | affinemess.com |
---|---|---|
location | Los Altos, CA | |
age | 44 | |
visits | member for | 4 years, 6 months |
seen | 15 hours ago | |
stats | profile views | 3,537 |
Math Circler, ex-Googler and Dad. Now at Facebook.
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. |
Jun 1 |
answered | Examples of theorems misapplied to non-mathematical contexts |
Jun 1 |
answered | Examples of theorems misapplied to non-mathematical contexts |
May 19 |
awarded | Nice Answer |