This workshop will be part of MSRI's Special Semester in Hyperplane Arrangements and Applications.

The combinatorial data associated with an arrangement of hyperplanes has proven to be core data for many algebraic and topological issues in arrangement theory. Conversely, the occurrence of certain combinatorial structures in arrangement theory has inspired research on generalizations in purely combinatorial settings.

The following topics will be central to the presentations and discussions
during this workshop:

combinatorial models for arrangements
oriented matroids
combinatorics of arrangement compactifications
phylogenetic trees
topology of partially ordered sets
combinatorial representation theory
random walks on arrangements


Confirmed speakers:

Christos Athanasiadis
Helene Barcelo
Ken Brown
Graham Denham
Persi Diaconis
Eva-Maria Feichtner
Phil Hanlon
Dmitry Kozlov
Nikolai Mnev
Alexander Postnikov
Jessica Sidman
Richard Stanley
Hiroaki Terao
Sasha Varchenko
Anatoly Vershik
Volkmar Welker


Monday, November 1

8:30 - 9:15 Registration

9:15 - 9:30 Welcome and Introduction

9:30 - 10:30 Ken Brown
Hyperplane face semigroups and their algebras.

10:30 - 11:00 Morning Tea (Sixth floor)

11:00 - 12:00 Persi Diaconis
Are there q-deformations of hyperplanes that are useful for shuffling?

12:00 - 2:00 Lunch Break

3:00 - 4:00 Jessica Sidman, MSRI/Evans Lecture: Equations defining subspace arrangements.

4:15 – 5:00 Richard Stanley, MSRI/Evans Lecture
The characteristic polynomial of a hyperplane arrangement.

Tuesday, November 2
8:10 - 9:10 Bernd Sturmfels: Introduction to Matroid Polytopes

9:30 - 10:30 Eva-Maria Feichtner
Nested set complexes in geometric combinatorics.

10:30 -11:00 Morning Tea (Sixth floor)

11:00 - 12:00 Dmitry Kozlov
Combinatorics of DeConcini-Procesi resolutions of the real permutation
action.

12:00 - 2:00 Lunch Break

2:00 - 3:00 Nicolai Mnev
Combinatorial stratifications of the Grassmanians: algebraic geometry and combinatorial fiber bundles.

3:00 - 3:30 Afternoon Tea (Sixth floor)

3:30 - 4:00 Federico Ardila
Bergman complexes and Coxeter arrangements.

4:14 - 4:45 Carsten Schultz
Cohomology rings of complex projective arrangements.

4:45 - 5:45 Reception (Sixth floor)

Wednesday, November 3

9:30 - 10:30 Michel Broue
Reductive groups over a field of x elements, x an indeterminate.

10:30 - 11:00 Morning Tea (Sixth floor)

11:00 - 12:00 Alexander Varchenko: The flag variety structure for solutions of the Bethe ansatz equations.

12:15 – 12:45 Laura Stevens
Combinatorics of rational functions and PBW expansions of the canonical U(n-)-valued differential form.

12:45 – 5:00 No scheduled talks

Thursday, November 4

9:30 - 10:30 Richard Stanley
Hyperplane arrangements and special relativity.

10:30 -11:00 Morning Tea (Sixth floor)

11:00 - 12:00 Volkmar Welker
Real rootedness and unimodality in discrete geometry.

12:00 - 2:00 Lunch Break

2:00 - 3:00 Alexander Postnikov
Hyperplane arrangements and ideals generated by powers of linear forms.

3:00 - 3:30 Afternoon Tea (Sixth floor)

3:30 - 4:00 Patricia Hersh
Some remarks on modular elements in lattices.

4:15 - 5:15 Anne Shepler
Reflection Groups and Modular Invariant Theory.

Friday, November 5

9:30 - 10:30 Christos Athanasiadis
Catalan and Narayana numbers for Weyl groups.

10:30 - 11:00 Morning Tea (Sixth floor)

11:00 - 12:00 Hiroaki Terao
On the multi-free arrangements.

12:00 - 2:00 Lunch Break

2:00 - 3:00 Alexandru Suciu
A look at right-angled Artin groups

3:00 - 3:30 Afternoon Tea (Sixth floor)

Funding

Important