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bio website gilkalai.wordpress.com
location Jerusalem
age 59
visits member for 5 years, 5 months
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Professor of Mathematics at the Hebrew University of Jerusalem and at Yale University

Nov
13
answered Fundamental Examples
Nov
12
answered Fundamental Examples
Nov
12
comment Fundamental Examples
I agree. I would also add the Fibonacci numbers en.wikipedia.org/wiki/Fibonacci_number . Fibonacci numbers lead to rational generating functions and Catalan numbers to rational generating functions. The Catalan numbers appear in an amazing number of different problems.
Nov
12
answered What is the first interesting theorem in (insert subject here)?
Nov
12
comment Fundamental Examples
Dear Andrew, I see your point; In any case, now that it is a community wiki some explenation for why an example is fundamental can be added by other participants.
Nov
12
answered Free, high quality mathematical writing online?
Nov
12
revised How Does Random Noise Typically Look?
edited tags
Nov
12
revised How Does Random Noise Typically Look?
edited tags; edited tags
Nov
12
answered Fundamental Examples
Nov
12
awarded  Self-Learner
Nov
12
comment Groupoid of moves on trivalent fatgraph
i did not understand the second move. But first what is a fatgraph?
Nov
12
revised Fundamental Examples
edited tags
Nov
12
answered Fundamental Examples
Nov
12
answered Fundamental Examples
Nov
12
answered Fundamental Examples
Nov
11
comment Fundamental Examples
I agree, complex projective planes (and spaces), real projective planes and spaces, and those over finite field are very important examples.
Nov
11
comment What precisely Is “Categorification”?
I came across this description, but I cannot imagine how Betti numbers were defined to start with.
Nov
11
comment What precisely Is “Categorification”?
what do you mean by moving from Betti numbers to homology; arnt the Betti number defined as the dimensions of homology to start with?
Nov
11
revised Fundamental Examples
added 80 characters in body
Nov
11
comment Fundamental Examples
I see, I guess it is a concrete example! (and even a popular one.)