Conjecture on counting unipotent irreducible Brauer characters

Let G\mathbf{G} be a reductive algebraic group with Frobenius endomorphism FF, let G=GFG=\mathbf{G}^F, and let pp be the characteristic of the defining field. For each \ell-special unipotent element uu, let Γu\Gamma_u^\ell be the \ell-special quotient defined from the projective characters of AG(u)A_{\mathbf{G}}(u). Let α\alpha_\ell be the number of pairs (u,x)(u,x), where uu runs over \ell-special unipotent elements of GG up to G\mathbf{G}-conjugacy and xM~(Γu)x\in\tilde{\mathcal{M}}_\ell(\Gamma_u^\ell).

Counting conjecture. Suppose that pp is good for G\mathbf{G}. Then α\alpha_\ell is the number of unipotent irreducible Brauer characters of GG.

In characteristic zero, analogous counts use canonical quotients associated with special unipotent classes. The conjecture proposes that the \ell-special quotient gives the correct count in positive characteristic, including the modular setting relevant to bad primes.

Sources & referencesView supporting material

Primary source

Reda Chaneb, “Basic sets for unipotent blocks of finite reductive groups in bad characteristic”, arXiv:1807.11325 (2018).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.