New York Applied Algebra Colloquium


Andrew Douglas (adouglas2 at
Delaram Kahrobaei (dkahrobaei at
Simon Smith (sismith at
Benjamin Steinberg (bsteinberg at
Time:          Fridays at 11:00 AM - 12:00 PM
Place:          CUNY Graduate Center, Room 3209
                   365 Fifth Avenue (between 34 and 35th streets), New York, NY.

Spring 2016 Schedule

 26Speaker: Artem Dudko (SUNY Stony Brook)
Title: On spectra of Koopman, groupoid and quasi-regular representations.
Abstract: One of the main sources of examples of unitary group representations is the three types of representations listed in the title. We discuss relations between spectra of these representations. In particular, we show that for an ergodic measure class preserving action of a countable group G on a standard Borel space the associated groupoid and quasi-regular representations are weakly equivalent and weakly contained in the Koopman representation.

 4Speaker: Christophe Hohlweg (UQUAM, Montreal, Canada)
Title: Artin-Tits Braid groups, Garside shadow and automata in Coxeter groups
Abstract: In this talk we will explain that the question of solving the conjugacy problem in the context of a general Artin-Tits Braid group reveals strong connections between the weak order of a Coxeter system (W,S) and finite states automata that recognizes the language of reduced words of elements of W over S. In particular, we will show that the smallest Garside shadow in W is finite, and by ricochet that finitely generated Artin-Tits groups have a finite Garside family. We will then discuss properties and open problems of a family of finite state automata built from finite Garside shadows.

 8Speaker: Conchita Martinez-Perez (University of Zaragoza, Spain)
Title: On the conjugacy search problem in certain family of metabelian groups
Abstract: We consider the conjugacy search problem for a family of metabelian groups of finite Pr\"ufer rank that generalizes the solvable Baumslag-Solitar groups. We describe an algorithm for this problem and
analyze its complexity, sowing that it is exponential and in some cases polynomial.