9,394 reputation
11116199
bio website gilkalai.wordpress.com
location Jerusalem
age 59
visits member for 5 years, 4 months
seen 15 hours ago
Professor of Mathematics at the Hebrew University of Jerusalem and at Yale University

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.)
Nov
11
answered Fundamental Examples
Nov
11
comment Fundamental Examples
Also if the example has a central importance but it is hard to say that it shaped the field, this is also OK!
Nov
11
comment Fundamental Examples
I prefer really a "real example" (rather than a theorem or a concept) and really a single example (rather than a link to many examples). I see no problem that the answeres's reputation will depend on the quality/popularity of the example. In many cases of basic examples a thorough explenation of how the example shaped the field is not needed.
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?