#### A combinatorial description of the totally nonnegative Grassmannian

Kelli Talaska

U.C. Berkeley

August 17, 2011

#### Non-Commutative Integrability, Paths and Quasi-determinants- Towards Non-Commutative Cluster Algebras

Philippe di Francesco

Saclay

August 15, 2011

#### Decision versus evaluation in algebraic complexity theory

Pascal Koiran

Ecole Normale Superieure de Lyon

August 5, 2011