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DTSTART:20260308T070000
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DTSTART:20251102T060000
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DTSTART;TZID=America/Toronto:20260924T143000
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URL:https://uwaterloo.ca/combinatorics-and-optimization/events/algebraic-an
 d-enumerative-combinatorics-seminar-lizzie-pratt
SUMMARY:Algebraic and Enumerative Combinatorics Seminar - Lizzie Pratt -\nO
 n-shell Forms and Hypertree Divisors
CLASS:PUBLIC
DESCRIPTION:SPEAKER:\n Lizzie Pratt\n\nAFFILIATION:\n Perimeter Institute\n
 \nLOCATION:\n MC 5417\n\nABSTRACT: On-shell forms are differential forms 
 on the Grassmannian\nwhich arise in particle physics. They are defined usi
 ng bipartite\ngraphs with n distinguished boundary vertices. Mathematical\
 ninvestigation of on-shell forms has largely focused on the case of\nplana
 r graphs\, where one can use tools developed by Postnikov in the\nstudy of
  the totally nonnegative Grassmannian. In this talk we develop\nthe mathem
 atics of nonplanar on-shell forms\, and explain how they\narise in physics
  and math. For certain forms on the Grassmannian\nGr(2\,n)\, we prove a de
 terminantal formula appearing in the physics\nliterature\, and give a conn
 ection to the hypertree divisors of\nCastravet and Tevelev.\n\nTHERE WILL 
 BE A PRE-SEMINAR PRESENTING RELEVANT BACKGROUND AT THE\nBEGINNING GRADUAT
 E LEVEL STARTING AT 1:30PM.
DTSTAMP:20260921T153240Z
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