BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Greg Muller (University of Oklahoma) DTSTART:20210406T150000Z DTEND:20210406T160000Z DTSTAMP:20260423T021134Z UID:OCAS/24 DESCRIPTION:Title: Sp aces of quasiperiodic sequences\nby Greg Muller (University of Oklahom a) as part of Online Cluster Algebra Seminar (OCAS)\n\n\nAbstract\nA "quas iperiodic space" is a vector space of sequences which are periodic up to a \nconstant factor. The moduli of such vector spaces are 1-dimensional exte nsions of\nGrassmannians\, and there are analogous positroid stratificatio ns of the former. I\nwill demonstrate that these "quasiperiodic positroid varieties" have a Y-type cluster\nstructure that is mirror dual to the X-t ype cluster structure on (the Plucker cone\nover) the corresponding positr oid variety. This structure is defined by extending a\nversion of Postniko v's boundary measurement map to the quasiperiodic case. Time\npermitting\, I will discuss an alternative construction of this boundary measurement\n map\, which uses the twist to construct a linear recurrence whose solution s are the\nspace in question. This provides a generalization of MGOST's co nnection between\nlinear recurrences\, friezes\, and the Gale transform. A motivating goal of this\nproject is to understand the tropical points of these quasiperiodic positroid\nvarieties\, as they parametrize the canonic al basis of theta functions on (the Plucker\ncone over) the corresponding positroid variety.\n LOCATION:https://researchseminars.org/talk/OCAS/24/ END:VEVENT END:VCALENDAR