What is a formula?

When
Start: 09/28/2016 - 4:15pm
End  : 09/28/2016 - 5:15pm

Category
Colloquium

Speaker
Igor Pak (UCLA)

Abstract

Integer sequences arise in a large variety of combinatorial problems as a way to count combinatorial objects.  Some of them have nice formulas, some have elegant recurrences, and some have nothing interesting about them at all.  Can we characterize when?  Can we even formalize what is a "formula"?  I will give a mini-survey aiming to answer these question with many examples.  At the end, I will present some recent results counting certain permutation classes, and finish with open problems.

Where
Kravis Center Lower Court 62, Claremont McKenna College