On the reducibility of characteristic varieties

Braden, Tom

doi:10.1090/S0002-9939-02-06469-9

On the reducibility of characteristic varieties
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Proc. Amer. Math. Soc. 130 (2002), 2037-2043 Request permission

Abstract:

We show that some monodromies in the Morse local systems of a conically stratified perverse sheaf imply that other Morse local systems for smaller strata do not vanish. This result is then used to explain the examples of reducible characteristic varieties of Schubert varieties given by Kashiwara and Saito in type $A$ and by Boe and Fu for the Lagrangian Grassmannian.

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