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FROM COMPLETE TO PARTIAL FLAGS IN GEOMETRIC EXTENSION ALGEBRAS

Published online by Cambridge University Press:  13 March 2017

JULIA SAUTER*
Affiliation:
Faculty of Mathematics, Bielefeld University, PO Box 100 131, 33501 Bielefeld, Germany e-mail: jsauter@math.uni-bielefeld.de
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Abstract

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A geometric extension algebra is an extension algebra of a semi-simple perverse sheaf (allowing shifts), e.g., a push-forward of the constant sheaf under a projective map. Particular nice situations arise for collapsings of homogeneous vector bundles over homogeneous spaces. In this paper, we study the relationship between partial flag and complete flag cases. Our main result is that the locally finite modules over the geometric extension algebras are related by a recollement. As examples, we investigate parabolic affine nil Hecke algebras, geometric extension algebras associated with parabolic Springer maps and an example of Reineke of a parabolic quiver-graded Hecke algebra.

Type
Research Article
Copyright
Copyright © Glasgow Mathematical Journal Trust 2017 

References

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