Title of Paper: Koszul duality and extensions of exponential functors

Author: Marcin Chalupnik

Email: mchal@mimuw.edu.pl

Abstract: We study  Koszul duality in the category of strict polynomial
functors. We compute Koszul duals for various functors and apply
these results to the problem of calculating  Ext--groups between
exponential functors. The main application is a full description
of the Ext--groups between twisted exterior and divided  powers
and between twisted symmetric and divided powers.