2 citations · 4 across the 8 of their papers we have counts for
12 papers
Base change and the Mackey formula in Deligne--Lusztig theory
Sean Cotner
Using ideas of Digne and recent work of Gaitsgory--Rozenblyum--Varshavsky, we show that Lusztig induction commutes with (a minor variant of) the Glauberman correspondence for large…
Modular functoriality for finite groups
Sean Cotner
We develop an extension of Deligne--Lusztig theory to certain (possibly infinite type) disconnected reductive groups arising from the special fibers of point stabilizers in the Bru…
Local Langlands functoriality for Yu's supercuspidals II: Fargues--Scholze's parametrization
Sean Cotner, Tony Feng
This is the second of two papers dedicated to the explicit computation of the Fargues--Scholze correspondence. We compute the Tate cohomology of cuspidal representations arising fr…
Local Langlands functoriality for Yu's supercuspidals I: Kaletha's parametrization
Sean Cotner, Tony Feng
This is the first of two papers dedicated to the explicit computation of the Fargues--Scholze correspondence. In this first part, we construct (inspired by, and extending, Kaletha'…
Central isogenies and conjugacy classes in reductive groups
Sean Cotner
Steinberg described the group of components of the centralizer of a semisimple element of a connected semisimple algebraic group as a subgroup of the fundamental group of .…
Connected components of the moduli space of L-parameters
Sean Cotner
Recently, in order to formulate a categorical version of the local Langlands correspondence, several authors have constructed moduli spaces of -valued L-parameters…
Hom schemes for algebraic groups
Sean Cotner
In SGA3, Demazure and Grothendieck showed that if and are smooth affine group schemes over a scheme and is reductive, then the functor of -homomorphism …
Morphisms of character varieties
Sean Cotner
Let be a field, let be (possibly disconnected) reductive groups over , and let be a finitely generated group. Vinberg and Martin have shown that the induce…
Springer isomorphisms over a general base scheme
Sean Cotner
We establish the existence of Springer isomorphisms for reductive group schemes over general base schemes. For this, we first study centralizers of fiberwise regular sections of re…
Lifting -Valued Galois Representations when
Jeremy Booher, Sean Cotner, Shiang Tang
In this paper we study the universal lifting spaces of local Galois representations valued in arbitrary reductive group schemes when . In particular, under certain tec…
Lefschetz theorems in flat cohomology and applications
Sean Cotner, Bogdan Zavyalov
We prove a version of the Lefschetz hyperplane theorem for fppf cohomology with coefficients in any finite commutative group scheme over the ground field. As consequences, we estab…
Centralizers of sections of a reductive group scheme
Sean Cotner
This paper proves a number of flatness results for centralizers of sections of a reductive group scheme over a general base scheme. To this end, we establish relative versions of t…