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bio website gilkalai.wordpress.com
location Jerusalem
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Professor of Mathematics at the Hebrew University of Jerusalem and at Yale University

Nov
11
comment What precisely Is “Categorification”?
Is moving from the notion of "Euler characteristic" to the notion of "homology" a sort of prototype to categorification?
Nov
11
answered Fundamental Examples
Nov
11
answered Fundamental Examples
Nov
11
answered What is the first interesting theorem in (insert subject here)?
Nov
11
comment Fundamental Examples
It is interesting, but this is a theorem, not an example right?
Nov
11
asked Fundamental Examples
Nov
11
answered Super-linear time complexity lower bounds for any natural problem in NP?
Nov
10
answered Where does a math person go to learn quantum mechanics?
Nov
10
awarded  Nice Question
Nov
10
comment Is formal proof (formalized mathematics) interesting to practicing mathematicians? To educators?
This is a fairly interesting question. There are many questions with no definite answers (like what is the most harmful heuristic) and I do not see the reason to close it.
Nov
10
asked What precisely Is “Categorification”?
Nov
9
comment f(f(x))=exp(x)-1 and other functions “just in the middle” between linear and exponential.
One answer, now in a community wiki, was marked as "the accepted answer". Feel free to edit it or to add more answers.
Nov
9
comment f(f(x))=exp(x)-1 and other functions “just in the middle” between linear and exponential.
To get roughly an intermediate growth rate of the kind we ask in the question we can define f(2^2^2^...^2)=(2^2^2^...^3) where in both sides we take a tower of length k, and then find a nice extrapolation.
Nov
9
comment How Does Random Noise Typically Look?
I improved the text, I hope it is clearer now.
Nov
9
revised How Does Random Noise Typically Look?
added 351 characters in body
Nov
9
comment How Does Random Noise Typically Look?
Thanks, Greg. Right. This is a question where the notion of random operation is rather clear in the quantum case (but never mind if this does not ring a bell) and not clear (to me) for the classic/digital case. I agree that random permutation for 0-1 strings of length n is not necessarily the right analog for random unitary operator on the space of n qubits but part of the question is to proposes the "right" analog.
Nov
9
asked How Does Random Noise Typically Look?
Nov
9
comment The Sylvester Gallai Theorem and Sections of Varieties with “Simple Topology”.
For example; suppose you have a 2 dimensional real algebraic variety V embedded in a high dimensional space (but not in any subspace). Can you find a plane L whose intersection with V affinely span V and belongs to one of a small number of homotopy type?
Nov
9
revised Why do functions in complex analysis behave so well? (as opposed to functions in real analysis)
added 270 characters in body
Nov
9
comment The Sylvester Gallai Theorem and Sections of Varieties with “Simple Topology”.
Thanks, Joe. I corrected it now.