KU Combinatorics Seminar
Spring 2009
The KU Combinatorics Seminar meets on Wednesdays,
3:00--4:00 PM in Snow 408.
Please contact Jeremy Martin
if you are interested in speaking.
Suggested topics for talks
This is a list of topics proposed at the organizational meeting on
January 21.
- Discrete Morse theory
- Polytopes
- Oriented matroids
- Design theory and error-correcting codes
- Integer partitions
- Lattice point enumeration
- Lie algebras and representation theory
Papers we'd like to understand:
- T. Chow, "You could have invented spectral sequences,"
Notices Amer. Math. Soc. 53 (2006), no. 1, 15--19.
- J. Herzog, T. Hibi and N. V. Trung, "Standard graded vertex cover
algebras, cycles and leaves," Trans. Amer. Math. Soc. 360 (2008),
no. 12, 6231--6249.
- W. Kook, V. Reiner and D. Stanton, "Combinatorial Laplacians of
matroid complexes," J. Amer. Math. Soc. 13 (2000), no. 1, 129--148.
- J. Stembridge, "Coxeter cones and their $h$-vectors," Adv.
Math. 217 (2008), no. 5, 1935--1961.
Schedule of talks
- Wednesday 1/21
Organizational meeting
- Wednesday 1/28
Jeremy Martin
Counting cubical spanning trees
- Wednesday 2/4
No seminar
- Wednesday 2/11
Jeremy Martin
Counting cubical spanning trees II
- Wednesday 2/18
Marge Bayer
Polytopes
- Wednesday 2/25
Jay Schweig and Jeremy Martin
Discussion of Kook, Reiner and Stanton,
"Combinatorial Laplacians of matroid complexes",
J. Amer. Math. Soc. 13 (2000), no. 1, 129--148.
- Wednesday 3/4
Tom Enkosky
Discussion of Herzog, Hibi, Trung, and Zheng,
"Standard graded vertex cover algebras, cycles and leaves",
Trans. Amer. Math. Soc. 360 (2008), no. 12, 6231--6249
- Wednesday 3/11
Jana Goodman (Emporia State University)
Discussion of K.Q. Ji,
"A
Combinatorial Proof of Andrews' Smallest Parts Partition Function
", Electronic
J. Comb. 15 (2008), article #N12.
- Wednesday 3/18
No seminar - Spring Break
- Wednesday 3/25
Brandon Humpert
Combinatorial Games and Surreal Numbers
- Wednesday 4/1
Brandon Humpert
Combinatorial Games and Surreal Numbers, II
- Wednesday 4/8
No seminar
- Wednesday 4/15
No seminar
- Wednesday 4/22
Fred Galvin
Cliques
Abstract: Some dull results and interesting problems inspired by the (easy) question: what is the minimum
number of
(maximal) cliques in an n-vertex graph and its complement? The answer to that question is n + 1; the minimizing graphs
were characterized in my first paper on graph theory, a joint work with M. M. Krieger. We get nontrivial questions by
changing "graph" to "hypergraph", or by changing "an n-vertex graph and its complement" to "an edge decomposition of the
complete graph on n vertices into k spanning subgraphs". Some partial results on these questions are obtained in my
posthumous paper with P. Erdos and M. M. Krieger.
- Wednesday 4/29
Jeremy Martin
Pseudo-Cell Posets
Abstract:
Jay Schweig and I are currently wondering when the edges of a ranked poset can be labeled
with integers so as to mimic the degrees of the attaching maps in a cell complex - and if
so, if one can say anything intelligent about the resulting Laplacian eigenvalues. I
will explain all this, likely very informally.
- Wednesday 5/6
TBA
Combinatorics seminars from previous semesters
Jeremy Martin's home page
Last updated Tue 4/29/09