Tsuyoshi Ito
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 Aug7 awarded Yearling Nov8 awarded Nice Answer Aug7 awarded Yearling Nov4 awarded Nice Answer Sep13 answered Boolean circuits and digraphs Sep1 comment Techniques for summing ratio of binomial coefficients I cannot move your question because I am not a moderator. Sep1 comment Techniques for summing ratio of binomial coefficients At least for me, this question is fairly uninteresting because it looks like just a random formula, and I fail to see why it is reasonable to expect that it has a nice closed-form expression (and also because I am not good at this kind of math). If you state why you are interested in this sum, some people may care more. Sep1 comment Techniques for summing ratio of binomial coefficients Moderators are not checking all comments to all questions. If you have a question to moderators, it is more reliable to flag your own question, choose “it needs ♦ moderator attention,” and explains why it needs moderator attention. Aug7 awarded Yearling Jul11 comment NP-completeness and NP problems @TonyK: If P=NP, why does switching from RSA to elliptic curve cryptosystems help? Jun13 comment Solving P vs NP with computer As you stated in the comments, you have made a few important assumptions to connect your answer to the question being asked. Instead of explaining those assumptions to me, why don’t you just state them in your answer? Making important assumptions implicitly is a bad way to talk about theory. Jun13 comment Solving P vs NP with computer @Quinn Culver: And what I meant is that undecidability of P=NP in a certain theory (whether neither P=NP nor P≠NP is provable in that particular theory) has nothing to do with the undecidability which Kaveh is talking about. Jun13 comment Solving P vs NP with computer @Quinn Culver: I am afraid that you are mixing up the decidability in the computability theory and the decidability (in a specific theory) in the formal logic theory. A single question (such as "is P=NP provable in ZFC?") cannot be undecidable in the computability sense. Jun13 comment Solving P vs NP with computer You generalized the question, pointed out that the generalized question is undecidable, and apparently concluded that the original question is hard. This is analogous to saying “solving the Hamiltonian circuit problem on the Petersen graph is hard because the Hamiltonian circuit problem is NP-complete.” Jun3 answered Minimizing Sum of Product May12 comment non-complete problem collapsing to a lower complexity class complete problem In the last paragraph, if P=NP, then it does mean that every P-complete problem under log-space reducibility is NP-complete under polynomial-time reducibility. I think that you meant to write the opposite: even if P=NP, it does not mean that every NP-complete problem under polynomial-time reducibility is P-complete under log-space reducibility. Apr7 revised How to simpify the way of calculating $(a^b \bmod c) \bmod d$? wording; tex Apr7 suggested approved edit on How to simpify the way of calculating $(a^b \bmod c) \bmod d$? Apr7 revised How to simpify the way of calculating $(a^b \bmod c) \bmod d$? wording; tex Apr7 suggested approved edit on How to simpify the way of calculating $(a^b \bmod c) \bmod d$?