Colloquium Series
Spring 2015
All talks are from 3:454:45 p.m. in the Colloquium Room, unless otherwise specified.

Apr22

TBAProf. Pam HarrisUSMA (West Point)Time: 03:45 PM

Apr07

Fast Times in Linear Programming: Early Success, Two Revolutions, and Continuing MysteriesProf. Margaret WrightNew York UniversityTime: 07:30 PM
View Abstract
Linear programming (LP), which isn't really about programming, is a simpletostate mathematical problem of enormous practical importance. The dramatic saga of LP solution methods began immediately after World War II with unexpected practical success that continued for more than 30 years despite theoretical reservations; next came two sweeping revolutions whose effects are often misunderstood. This talk will describe mathematical and computational issues from the history of LP, enlivened by controversy and international politics, as well as some remaining mysteries.

Apr01

Tools from Computational Topology, with applications in the life sciencesProf. Sarah DayCollege of William and MaryTime: 03:45 PM
View Abstract
The field of topology, and in particular computational topology, has produced a powerful set of tools for studying both model systems and data measured directly from physical systems. I will focus on three classes of topological tools: computational homology, topological persistence, and, very briefly, Conley index theory. To illustrate their use, I will discuss recent projects studying coupledpatch population dynamics, flickering red blood cells, and pulsecoupled neurons.

Mar04

Strong shift equivalence and algebraic KtheoryProf. Mike BoyleUniversity of MarylandTime: 03:45 PM
View Abstract
This will be a colloquium talk, assuming no background in Ktheory. Let R (always assumed to contain 0 and 1) be a subset of a ring. Let A,B be square matrices over R (not necessarily of equal size). A and B over R are elementary strong shift equivalent over R (ESSER) if there exist matrices U,V over R such that A=UV and B=VU. A and B are strong shift equivalent over R (SSER) if they are connected by a chain of elementary strong shift equivalences. If R is a ring, what does it mean for A and B to be strong shift equivalent? This question is motivated by classification problems in symbolic dynamics, as I'll describe, but is natural enough on its own. In his 1973 Annals paper, Williams took the first step, introducing shift equivalence (SE) as an invariant of strong shift equivalence. Whether SE implies SSE for a ring R remained open. It turns out that for a ring R, the refinement of SE by SSE can be nontrivial, and is captured exactly by the algebraic Ktheory group NK_1(R). This is joint work with Scott Schmieding.

Jan21

Special loci for the moduli space of rational mapsLT Brian StoutUSNATime: 03:45 PM