BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Hunter Spink (Stanford) DTSTART:20220325T190000Z DTEND:20220325T200000Z DTSTAMP:20260407T214323Z UID:agstanford/82 DESCRIPTION:Title: A new Chern character for "classical Lie type" combinatorics\nby H unter Spink (Stanford) as part of Stanford algebraic geometry seminar\n\n\ nAbstract\nFor X of “classical Lie type” (formally such that X has a G KM torus action where all characters are of the form t_i\, t_i+t_j\, and t _i-t_j for various i\,j)\, we adapt for combinatorial applications the (eq uivariant) Hirzebruch-Riemann-Roch framework which computes Euler characte ristics of vector bundles via cohomological computations\, extending previ ous joint work in type A with Andrew Berget\, Chris Eur\, and Dennis Tseng .\n\nThis framework directly relates the structure sheaf of Schubert varie ties to Grothendieck polynomials\, produces formulas (some of them new) re lating the number of lattice points and volumes for type A and B generaliz ed permutahedrons\, and when applied to ample equivariant vector bundles o n toric varieties is a key component in recent progress on establishing an d unifying results on the log-concavity of sequences associated to matroid s and delta-matroids.\n\n[This is joint work with Chris Eur\, Alex Fink\, and Matthew Larson.]\n\nThe synchronous discussion for Hunter Spink’s ta lk is taking place not in zoom-chat\, but at https://tinyurl.com/2022-03-2 5-hs (and will be deleted after ~3-7 days).\n LOCATION:https://researchseminars.org/talk/agstanford/82/ END:VEVENT END:VCALENDAR