Algebra Seminar: Achar -- Koszul duality and mixed geometry

The Algebra Seminar next Friday 3 June will be given by Pramod Achar.  

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Speaker: Pramod Achar (Louisiana State University) 

Date: Friday 3 June 

Time: 12.05-12.55pm 

Venue: Carslaw 175 

Title: 

Koszul duality and mixed geometry 

Abstract: 

Since the seminal work of Beilinson-Ginzburg-Soergel in the mid-1990s, the phenomenon of
Koszul duality -- a subtle kind of symmetry between simple modules and projective
modules over a ring -- has played an important role in representation theory.  A key
example comes from the geometry of flag varieties, where one can see Koszul duality by
looking at mixed perverse sheaves or mixed Hodge modules -- well, almost.  I will
explain Koszul duality and mixedness in elementary terms, and I will discuss what goes
wrong with those mixed categories and (following Beilinson-Ginzburg-Soergel) how to fix
them.  I will also discuss more recent developments from joint work with S. Riche and
S. Kitchen.  

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