# Some new constructions of supercuspidal mod p representations of GL_2(F), for a p-adic field F

`2022-11-09 10:30:00``2022-11-09 11:30:00``Some new constructions of supercuspidal mod p representations of GL_2(F), for a p-adic field F``Let F / Q_p be a finite extension. In contrast to the situation for complex representations, very little is known about the irreducible supercuspidal mod p representations of GL_n(F), except in the case GL_2(Q_p). If F / Q_p is unramified and r is a generic irreducible two-dimensional mod p representation of the absolute Galois group of F, then nearly 15 years ago Breuil and Paskunas gave a beautiful construction of an infinite family of diagrams giving rise to supercuspidal mod p representations of GL_2(F) with GL_2(O_F)-socle consistent with the Breuil-Mézard conjecture for r. While their construction is not exhaustive, various local-global compatibility results obtained by a number of mathematicians in the intervening years indicate that it is sufficiently general to capture the mod p local Langlands correspondence for generic Galois representations. In this talk we will review the ideas mentioned above and discuss how to move beyond them to consider ramified p-adic fields F, or non-generic representations r for unramified F. We will describe a simple construction of supercuspidal representations for certain ramified F and generic r; while this is the first such example for ramified F, it involves a breakage of symmetry that makes it unlikely to shed light on the local Langlands correspondence for r. We then discuss works in progress with Ariel Weiss and with Reem Waxman that aim to give a “correct” generalization of the Breuil-Paskunas construction. A new feature is that we work with the category of mod p representations of GL_2(R), where R is a quotient ring of O_F that is larger than the residue field. ================================================ https://us02web.zoom.us/j/87856132062 Meeting ID: 878 5613 2062``Third floor seminar room and Zoom``אוניברסיטת בר-אילן - Department of Mathematics``mathoffice@math.biu.ac.il``Asia/Jerusalem``public`Let F / Q_p be a finite extension. In contrast to the situation for complex representations, very little is known about the irreducible supercuspidal mod p representations of GL_n(F), except in the case GL_2(Q_p). If F / Q_p is unramified and r is a generic irreducible two-dimensional mod p representation of the absolute Galois group of F, then nearly 15 years ago Breuil and Paskunas gave a beautiful construction of an infinite family of diagrams giving rise to supercuspidal mod p representations of GL_2(F) with GL_2(O_F)-socle consistent with the Breuil-Mézard conjecture for r. While their construction is not exhaustive, various local-global compatibility results obtained by a number of mathematicians in the intervening years indicate that it is sufficiently general to capture the mod p local Langlands correspondence for generic Galois representations.

In this talk we will review the ideas mentioned above and discuss how to move beyond them to consider ramified p-adic fields F, or non-generic representations r for unramified F. We will describe a simple construction of supercuspidal representations for certain ramified F and generic r; while this is the first such example for ramified F, it involves a breakage of symmetry that makes it unlikely to shed light on the local Langlands correspondence for r. We then discuss works in progress with Ariel Weiss and with Reem Waxman that aim to give a “correct” generalization of the Breuil-Paskunas construction. A new feature is that we work with the category of mod p representations of GL_2(R), where R is a quotient ring of O_F that is larger than the residue field.

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https://us02web.zoom.us/j/87856132062

Meeting ID: 878 5613 2062

Last Updated Date : 01/11/2022