## Daniel Ruberman, Brandeis University

Rohlin's invariant and gauge theory

**
Thursday October 20, 4:00PM,
Herman Brown 227**
Rohlin's theorem about the signature of smooth, closed
spin 4-manifolds leads to an interesting Z/2-valued invariant of
3-dimensional manifolds. I will describe some joint work with
Nikolai Saveliev about a version of this invariant that can be
applied to certain non-simply-connected 4-manifolds. We have given
an interpretation of this invariant in terms of gauge theory, and I
will discuss some applications of this interpretation.