Semi-infinite combinatorics in representation theory

  • Martina Lanini

    Edinburgh University, UK
Semi-infinite combinatorics in representation theory cover

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Abstract

In this work we discuss some appearances of semi-infi nite combinatorics in representation theory. We propose a semi-in finite moment graph theory and we motivate it by considering the (not yet rigorously de fined) geometric side of the story. We show that it is possible to compute stalks of the local intersection cohomology of the semi-infi nite flag variety, and hence of spaces of quasi maps, by performing an algorithm due to Braden and MacPherson.