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bio website affinemess.com
location Los Altos, CA
age 44
visits member for 4 years, 6 months
seen 20 hours ago
Math Circler, ex-Googler and Dad. Now at Facebook.

Mar
16
comment Properties of Graphs with an eigenvalue of -1 (adjacency matrix)?
If G->B is a covering map (in the topological sense), then G inherits all the eigenvalues of B (just choose an eigenfunction that is uniform on the fibers). So, for instance, any graph which covers K_n for any n has -1 as an eigenvalue. The cycle of length 3k covers the triangle, which is another way to explain Kevin's example.
Mar
16
awarded  Nice Answer
Mar
16
awarded  Popular Question
Mar
14
awarded  Enlightened
Mar
14
awarded  Nice Answer
Mar
12
comment Books you would like to see translated into English.
That's +10 from me, too.
Mar
10
answered A historical question: Hurwitz, Luroth, Clebsch, and the connectedness of M_g
Mar
9
revised Why are the sporadic simple groups HUGE?
added 2 characters in body
Mar
9
comment If 2^x and 3^x are integers, must x be as well?
This answer was given by Gerry. I just added the link to Wikipedia.
Mar
9
revised If 2^x and 3^x are integers, must x be as well?
Added wikipedia link
Mar
9
comment If 2^x and 3^x are integers, must x be as well?
Very interesting! Just to make sure I understand - does this generalize the "n^x for all n" version only, or can it be applied to "2,3,5" and "2,3" as well?
Mar
9
accepted If 2^x and 3^x are integers, must x be as well?
Mar
9
comment If 2^x and 3^x are integers, must x be as well?
@jef: the best hint I can think of is "calculus of differences".
Mar
9
awarded  Good Question
Mar
9
awarded  Nice Question
Mar
9
asked If 2^x and 3^x are integers, must x be as well?
Mar
8
comment Criteria for accepting an invitation to become an editor of a scientific journal
I think the following criterion is somewhat rational: when the publishers of a new journal solicit help for the editorial board, they understand that people will be asking themselves exactly the kind of question you are asking. Therefore they make an effort to establish the reputation of the new journal in the email - providing references to editors who have already joined, explaining why a new journal in this field is called for, contrasting it with similar journals etc. On the other hand they don't say anything about the submission process since this is completely irrelevant.
Mar
6
answered Teaching Methods and Evaluating them
Mar
3
comment Diameter of m-fold cover
I must be missing something - why do you say that L(bi) < L(ai) in the second paragraph? Why is that a strict inequality?
Feb
19
revised How should I approximate real numbers by algebraic ones?
deleted 1 characters in body