[theory-seminar] Persi Diaconis combinatorics/theory seminar double-header

[Gregory Valiant]

Hi Everyone,
Persi Diaconis will be giving [different] back-to-back talks at the
Combinatorics seminar (@3pm) and theory seminar (@4:15) today.
Details below.


Combinatorics Seminar:
Room: 384-H
Title: Derangements for grownups
Abstract: The combinatorics of permutations with restricted positions
leads to many corners of mathematics. I'll begin with a statistical
example from astrophysics. This leads to rook theory, Lie algebra
cohomology and characterizations of graph classes by excluded minors.
Derangements can also be looked at as enumerative group theory (Polya
theory). This extends to other groups and classical symmetric function
theory. I will try to say all of this 'in English'.

Theory Seminar:
Room: Gates 463
Title: Using Algorithms to Prove Theorems
Abstract: Sometimes, a clever algorithm gives a representation that
allows theorems to be proved.  I will illustrate with Stam's algorithm
for generating random set partitions (so there are five set partitions
of three things: 1/2/3, 12/3, 13/2, 23/1, 123) a variety of statistics
have resisted analysis (particularly the number of crossings).  I hope
that this is the tip of an iceberg, but the audience will have to
help.  This is joint work with Daniel Kane, Bobbie Chern, and Rob
Rhodes.