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Character Sheaves on Reductive Lie Algebras in Positive Characteristic (2404.19210v2)
Published 30 Apr 2024 in math.RT and math.AG
Abstract: We prove a microlocal characterisation of character sheaves on a reductive Lie algebra over an algebraically closed field of sufficiently large positive characteristic: a perverse irreducible G-equivariant sheaf is a character sheaf if and only if it has nilpotent singular support and is quasi-admissible. We also present geometric proofs, in positive characteristic, of the equivalence between being admissible and being a character sheaf, and various characterisations of cuspidal sheaves, following the work of Mirkovi\'c.