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PRODID:-//Memento EPFL//
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SUMMARY:GAAG seminar - Periodic pipe dreams for matrix positroid varieties
DTSTART:20260930T100000
DTEND:20260930T120000
DTSTAMP:20260928T174255Z
UID:14359eedea7134922680c4d0818553766dbe7fb8880eb7ef733cd1a1
CATEGORIES:Conferences - Seminars
DESCRIPTION:Paul Zinn-Justin (University of Melbourne)\nI will introduce "
 periodic pipe dreams"\, a combinatorial model that first appeared in [Fan 
 Guo Su Xiong '25]. I will then give it a full geometric interpretation in
  terms of new varieties called matrix positroid varieties. Defining these 
 involves infinite matrices that are not simply periodic\, as in the case o
 f ordinary positroid varieties\, but rather periodically twisted by a diag
 onal matrix. Matrix positroid varieties are indexed by arbitrary juggling 
 patterns\, and we will briefly discuss their combinatorics. We will then c
 alculate their Chern–Schwartz–MacPherson classes using a multiparamete
 r deformation of their characteristic cycles\, which we then degenerate in
 to a union of varieties indexed by periodic pipe dreams. This is joint wor
 k with Allen Knutson.
LOCATION:CM 1 517 https://plan.epfl.ch/?room==CM%201%20517
STATUS:CONFIRMED
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