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DTSTART;TZID=America/Detroit:20261023T150000
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SUMMARY:Workshop / Seminar:Unexpected torus action on toric Richardson varieties
DESCRIPTION:This talk focuses on Richardson varieties in the complete flag variety\, which are intersections of a Schubert variety with an opposite Schubert variety. Richardson varieties are indexed by intervals in the Bruhat order on the symmetric group. In joint work with E. Gorsky and M. Sherman-Bennett\, we study the following question: when is a Richardson variety a toric variety? All Richardson varieties admit an action by an (n-1)- dimensional torus in SL_n\, called the standard torus\, which also acts on the complete flag variety. The Richardson varieties which are toric varieties with respect to the standard torus were classified independently by Anderson and Tsukerman--Williams. We found that there are many additional toric Richardson varieties\, which we call \"so muchunexpected”. In this rather expository talk\, I will classify toric Richardson varieties using the combinatorics of Bruhat intervals and focus on describing this \"unexpected\" torus action using the Marsh--Rietsch parametrization on open Richardson varieties. If time permits\, I will mention my ongoing research in this direction.
UID:149981-21907760@events.umich.edu
URL:https://events.umich.edu/event/149981
CLASS:PUBLIC
STATUS:CONFIRMED
CATEGORIES:Mathematics
LOCATION:East Hall - 4088
CONTACT:
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