**Date: **
16:00,
Tuesday, January 24, 2017

**Speaker: **
Shaull Almagor

**Venue: **IST Austria

We consider the following problem: given a dxd matrix A and two polytopes P and Q, is there a natural number n such that A^n P intersects Q. We show that the problem can be decided in PSPACE for dimension at most three. As in previous works, decidability in the case of higher dimensions is left open, as the problem is known to be hard for long-standing number-theoretic open problems.

The talk is self-contained and assumes no background from the audience. As such, the talk will include short introductions to various mathematical tools, such as representation of algebraic numbers, the theory of real-closed fields, and quantifier elimination.