Oriented Matroids from Triangulations of Products of Simplices (note the unusual time: 4pm)

Combinatorics Seminar
Friday, October 23, 2020 - 4:00pm for 1 hour (actually 50 minutes)
https://bluejeans.com/751242993/PASSWORD (To receive the password, please email Lutz Warnke)
Chi Ho Yuen – Brown University – https://yuenchiho.github.io/
Lutz Warnke

We introduce a construction of oriented matroids from any triangulation of a product of two simplices, extending the regular case which follows from signed tropicalization. For this, we use the structure of such a triangulation in terms of polyhedral matching fields. The oriented matroid is composed of compatible chirotopes on the cells in a matroid subdivision of the hypersimplex, which might be of independent interest. We will also describe the extension to matroids over hyperfields and sketch some connections with optimization. This is joint work with Marcel Celaya and Georg Loho; Marcel Celaya will be giving a talk on the topological aspect of the work at the algebra seminar next week.

Please note the unusual time: 4pm