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SUMMARY:UNIVERSE+ Online Seminars
DTSTART:20261028T150000Z
DTEND:20261028T160000Z
DTSTAMP:20261025T035500Z
UID:indico-event-12280@indico.mpp.mpg.de
DESCRIPTION:Speakers: Lizzie Pratt (Perimeter Institute for Theoretical Ph
 ysic)\n\n\nThis is the Online Seminar Series of the ERC Synergy Grant UNIV
 ERSE+ \n\nOctober 28\, 4:00pm: Lizzie Pratt \n\n           "Mathem
 atics of Nonplanar On-Shell Forms"\nAbout the speaker:Lizzie is a mathemat
 ician interested in combinatorial algebraic geometry and geometric structu
 res arising in scattering amplitudes. Lizzie graduated from Berkeley in 20
 26 under the supervision of Bernd Sturmfels\, spent five months as a Chanc
 ellor's Fellow at UC Davis\, and is now a postdoctoral fellow at Perimeter
  Institute for Theoretical Physics. \nAbstract:On-shell forms are differe
 ntial forms on the Grassmannian which represent leading singularities of c
 ertain amplitudes. Mathematical investigation of on-shell forms has largel
 y focused on the case of planar graphs\, where one can use tools developed
  by Postnikov in the study of the totally nonnegative Grassmannian. In thi
 s talk we develop the mathematics of nonplanar on-shell forms from first p
 rinciples. In the MHV case (k=2) we give a proof of a determinantal formul
 a appearing in prior physics literature\, and exhibit a connection to the 
 hypertree divisors of Castravet and Tevelev. This is based on joint work w
 ith Artyom Lisitsyn\, Melissa Sherman-Bennett\, and Jaroslav Trnka.\n \nY
 our registration is valid for the entire UNIVERSE+ Seminar Series\, so the
 re is no need to register individually for each session.\nThis activity is
  part of the ERC Synergy Grant UNIVERSE+ www.positive-geometry.com\, funde
 d by the European Union (ERC\, UNIVERSE PLUS\, 101118787). Views and opini
 ons expressed are however those of the author(s) only and do not necessari
 ly reflect those of the European Union or the European Research Council Ex
 ecutive Agency. Neither the European Union nor the granting authority can 
 be held responsible for them.\n\n\nhttps://indico.mpp.mpg.de/event/12280/
URL:https://indico.mpp.mpg.de/event/12280/
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