University of Michigan/Texas State University, USA

Room 3433

Seminar series on discrete mathematics @ Dept. of Mathematical Sciences, KAIST.

Fun with wires

Suho Oh

University of Michigan/Texas State University, USA

University of Michigan/Texas State University, USA

2014/08/01 Friday 4PM-5PM

Room 3433

Room 3433

Wiring diagrams are widely used combinatorial objects that are mainly used to describe reduced words of a permutation. In this talk, I will mention a fun property I recently found about those diagrams, and then introduce other results and problems related to this property.

Matchings in Bipartite Graphs and the Generalized Permutohedra

Suho Oh (오수호)

Department of Mathematics, MIT, Cambridge, MA, USA

Department of Mathematics, MIT, Cambridge, MA, USA

2011/1/21 Fri 4PM-5PM

A transversal matroid is a collection of objects that encodes maximal matchings in a bipartite graph. Generalized permutohedra is a class of polytopes obtained by deforming the permutohedron. We introduce a nice bijection that allows one to view transversal matroids as set of lattice points inside a generalized permutohedron. As a corollary, we solve a special case of the 30-year old conjecture by Stanley on matroids and pure O-sequences. The talk will be elementary and purely combinatorial.