# Geometric Analysis and Topology Seminar

#### Geometric Topology Meets Computational Complexity

**Speaker:**
Greg Kuperberg, UC Davis

**Location:**
Warren Weaver Hall 1302

**Date:**
Thursday, October 5, 2017, 12:15 p.m.

**Synopsis:**

Now that the geometrization conjecture has been proven, and the virtual Haken conjecture has been proven, what is left in 3-manifold topology? One remaining topic is the computational complexity of geometric topology problems. How difficult is it to distinguish the unknot? Or 3-manifolds from each other? The right approach to these questions is not just to consider quantitative complexity, i.e., how much work they take for a computer; but also qualitative complexity, whether there are efficient algorithms with one or another kind of help. I will discuss various results on this theme, such as that knottedness and unknottedness are both in NP; and I will discuss high-dimensional questions for context.