Title:	The Alexander polynomial of knots and tangles
Speaker:	Stephen Bigelow (UCSB)
Abstract:	In 1923, Alexander discovered the first polynomial knot invariant. Certain local changes to a knot affect the Alexander polynomial in predictable ways. Until recently, there was no Alexander invariant of the local pieces of a knot, or "tangles". Now Dror Bar-Natan has defined an Alexander invariant of a "circuit algebra" which is a super-generalization of knots, tangles, braids and more. I will attempt to explain this, with pictures and examples.