Spring 2017

The Combinatorics Seminar meets on Friday in Snow 408 from 3-4pm.

Please contact Jeremy Martin if you are interested in speaking.

**Friday 1/20**

No seminar

**Friday 1/27**

Organizational meeting

**Friday 2/3**

Marge Bayer/Jeremy Martin

Background
material for the paper *Relative
Stanley-Reisner theory and Upper Bound Theorems for Minkowski
sums* by Karim Adiprasito and Raman Sanyal [Publ. Math. IHES 124
(2016), 99-163]

**Friday 2/10**

Long Dao

*Stanley's proof of the Upper Bound Conjecture for simplicial spheres*

**Friday 2/17**

Bennet Goeckner

*Balanced Cohen-Macaulay complexes*

**Friday 2/24**

Joseph Doolittle

*Cayley polytopes and Minkowski sums*

**Friday 3/3**

No seminar

**Friday 3/10**

Cass Sherman (Oklahoma State)

*Polynomials of Stretched Littlewood-Richardson Numbers*

__Abstract:__
Littlewood-Richardson (L-R) coefficients describe multiplicities of irreducible
representations in a tensor product. They depend on combinatorial parameters called
weights. These can be stretched by any positive integer. For a fixed set of weights,
one considers the effect of stretching on L-R numbers, i.e. the function which
associates to an integer \(N\) the L-R coefficient with the weights stretched by \(N\). This
function is a polynomial with many nice properties. In this talk, we will discuss
these properties and their relationship to the algebraic geometry of a certain
polarized moduli space \((M,L)\), connected to the L-R numbers by a famous theorem of
Borel-Weil.

**Friday 3/17**

TBA

**Friday 3/24**

No seminar (Spring Break)

**Friday 3/31**

Ken Duna

Title TBA

**Friday 4/7**

Jeremy Martin

*Simplicial and Cellular Spanning Trees*

__Abstract:__ Counting spanning trees in graphs is a classical
topic, dating back at least as far as Kirchhoff's discovery of the
Matrix-Tree Theorem in the 1840s. Much of the theory of tree
enumeration carries over to the higher-dimensional setting, where the
graph is replaced with a simplicial or CW-complex - but with a twist. I
will strive to make this talk should be accessible to all graduate
students.

**Friday 4/14**

Arturo Jaramillo

*Cumulants and moments for products of free random variables*

**Friday 4/21**

No seminar

**Friday 4/28**

Brandon Caudell

**Oral Presentation for Departmental Honors**

**Friday 5/5**

No seminar (Stop Day)

For seminars from previous semesters, please see the KU Combinatorics Group page.

Last updated Thu 5/15/17