Type: Seminar

Distribution: World

Expiry: 31 Oct 2016

CalTitle1: Group Actions Seminar: Li

Calendar2: 31 Oct 2016 1500-1600

CalLoc2: Carslaw 373

CalTitle2: Group Actions Seminar: Thomas

Auth: timothyb@como.maths.usyd.edu.au

The next Group Actions Seminar will be on Monday 31 October at the University of Sydney. The schedule, titles and abstracts are below. -------------------------------------------------------------------------- 12 noon-1pm, Carslaw 373 Speaker: Huanhuan Li, Western Sydney University Title: The projective Leavitt complex Abstract: For a finite quiver Q without sources, we consider the corresponding radical square zero algebra A. We construct an explicit compact generator for the homotopy category of acyclic complexes of projective A-modules. We call such a generator the projective Leavitt complex of Q. This terminology is justified by the following result: the opposite differential graded endomorphism algebra of the projective Leavitt complex of Q is quasi-isomorphic to the Leavitt path algebra of Q^{op}. Here, Q^{op} is the opposite quiver of Q and the Leavitt path algebra of Q^{op} is naturally Z-graded and viewed as a differential graded algebra with trivial differential. 1-3pm Lunch 3-4pm, Carslaw 373 Speaker: Anne Thomas, University of Sydney Title: Commensurability classification of certain Coxeter groups and amalgams of free groups Abstract: Two groups G and H are (abstractly) commensurable if they have finite index subgroups G’ and H’ so that G’ and H’ are abstractly isomorphic. Commensurability in this sense is an equivalence relation on abstract groups. We give explicit necessary and sufficient conditions for commensurability within certain families of Coxeter groups and amalgams of free groups. Our methods are topological, and involve a new geometric realisation of the Coxeter groups involved. This is joint work with Pallavi Dani and Emily Stark. -------------------------------------------------------------------------