Combinatorics Seminar

The combinatorics seminar in Fall 2018 will be held in room LIT368 during 6th period (12:50-01:40PM).

Date Speaker Title / Abstract
Tuesday, August 28 No seminar
Tuesday, September 4 Ms. Churni Gupta Title: Counting Lyndon Factors
Tuesday, September 11 Cancelled
Tuesday, September 18 Ms. Lindsey Grigsby Title: Three Problems in Combinatorial Asymptotics

Abstract: I will present a paper (by Herbert Wilf) which answers three questions:

(1) How many different sizes of cycles does a permutation of n letters have (on average, when n is large)?
(2) How many different sizes of parts does a partition of the integer n have (on average, when n is large)?
(3) How many subspaces does an n-dimensional vector space over a finite field have, when n is large?

These are motivated by simpler, previously-understood questions (for the first, “How many cycles does a permutation of n letters have, on average, when n is large?”), but have surprising answers. Also interesting is that Wilf’s method in this paper can be used to find many other generating functions. If for some combinatorial class, the generating function for the number of objects of size n whose parts have sizes which lie in a set S has a certain form, then Wilf’s method can be used to find the generating function for the number of objects of size n whose parts have exactly k different sizes.

Tuesday, September 25 No seminar
Tuesday, October 2 No seminar
Tuesday, October 9 No seminar
Tuesday, October 16 TBA
Tuesday, October 23 Prof. Vincent Vatter
Tuesday, October 30 Prof. Miklós Bóna
Tuesday, November 6 Prof. Dana Bartosova
Tuesday, November 13 Prof. Andrew Vince
Tuesday, November 20 TBA
Tuesday, November 27 TBA
Tuesday, December 4 Prof. Bruce Sagan