4 papers
On the normality of the commuting scheme
Jack Sempliner, Xiangqian Yang
If is a connected reductive algebraic group over a field of characteristic , we show that both the Lie-theoretic and group-theoretic commuting schemes associated to $…
A geometric Jacquet--Langlands correspondence for Shimura varieties
Pol van Hoften, Jack Sempliner
We formulate a conjecture predicting the existence of exotic isomorphisms between Igusa stacks associated to different Shimura data whose underlying groups are pure inner forms of…
Cocycles for Kottwitz cohomology
Jack Sempliner, Richard Taylor
In his work on defining the pointed set B(G) for all local and global fields, Kottwitz introduced certain Galois gerbes and considered their 'algebraic' cohomology with values in a…
On the Piatetski-Shapiro construction for integral models of Shimura varieties
Pol van Hoften, Jack Sempliner
We study the Piatetski-Shapiro construction, which takes a totally real field F and a Shimura datum (G,X) and produces a new Shimura datum (H,Y). If F is Galois, then the Galois gr…