## Colloquium: Cataland

Author: UNB

Posted on Mar 17, 2014

Category:
Seminars and Colloquia

#### Colloquium

#### Cataland

##### Nathan Williams (Université du Québec à Montréal)

##### Thursday, March 20, 2014 at 3:30 pm

##### Tilley Hall Room 5

I will talk about two combinatorial miracles relating poset-theoretic objects with Coxeter-theoretic objects. The first miracle is that there are the same number of linear extensions of the root poset as reduced words of the longest element (occasionally), while the second is that there are the same number of order ideals in the root poset as certain generality at which we should expect such statements to be true.
##### Nathan Williams is a Post-Doctoral Fellow at Université du Québec à Montréal.