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UID:20250712T113752EDT-1341J08DU8@132.216.98.100
DTSTAMP:20250712T153752Z
DESCRIPTION:Total positivity for the Lagrangian Grassmannian.\n\nThe positr
 oid decomposition of the Grassmannian refines the well-known Schubert deco
 mposition\, and has a rich geometrical and combinatorial structure. There 
 are a number of interesting combinatorial posets which describe the closur
 e relations among positroid varieties\, just as Young diagrams give the cl
 osure relations among Schubert varieties. In addition\, Postnikov's bounda
 ry measurement map gives a family of parametrizations for each positroid v
 ariety. The domain of each parametrization is the space of edge weights of
  a weighted planar network. The positroid stratification of the Grassmanni
 an provides an elementary example of Lusztig's theory of total nonnegativi
 ty for partial flag varieties\, and has remarkable applications to particl
 e physics. In this talk\, we extend the combinatorics of positroid varieti
 es to the Lagrangian Grassmannian\, the moduli space of maximal isotropic 
 subspaces with respect to a symplectic form.\n
DTSTART:20170210T183000Z
DTEND:20170210T193000Z
LOCATION:PK-4323\, CA\, Pavillon Président-Kennedy
SUMMARY:Rachel Karpman\, Ohio State University
URL:/mathstat/channels/event/rachel-karpman-ohio-state
 -university-265570
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