#### 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

#### Complexity Problems for Diophantine Equations

Jeffrey Lagarias

University of Michigan

August 4, 2011