BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250918T080429EDT-3557juwK34@132.216.98.100 DTSTAMP:20250918T120429Z DESCRIPTION: THE QUEBEC-VERMONT NUMBER THEORY SEMINAR\n\n \n\nTitle: Non-re gular loci in the Emerton-Gee stack for GL2\n\nAbstract: Let K be a finite extension of Qp. The Emerton-Gee stack for GL2 is a stack of etale (phi\, Gamma)-modules of rank two. Its reduced part\, X\, is an algebraic stack of finite type over a finite field\, and can be viewed as a moduli stack o f two dimensional mod p representations of the absolute Galois group of K. By the work of Caraiani\, Emerton\, Gee and Savitt\, it is known that in most cases\, the locus of mod p representations admitting crystalline lift s with specified regular Hodge-Tate weights is an irreducible component of X. Their work relied on a detailed study of a closely related stack of et ale phi-modules which admits a map from a stack of Breuil-Kisin modules wi th descent data. In our work\, we assume K is unramfied and further study this map with a view to studying the loci of mod p representations admitti ng crystalline lifts with small\, non-regular Hodge-Tate weights. We ident ify these loci as images of certain irreducible components of the stack of Breuil-Kisin modules and obtain several inclusions of the non-regular loc i into the irreducible components of X. This is joint work with Rebecca Be llovin\, Neelima Borade\, Anton Hilado\, Heejong Lee\, Brandon Levin\, Dav id Savitt and Hanneke Wiersema.\n DTSTART:20230928T143000Z DTEND:20230928T153000Z LOCATION:Room 1104\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Kalyani Kansai (IAS) URL:/mathstat/channels/event/kalyani-kansai-ias-351300 END:VEVENT END:VCALENDAR