Clozel–Harris–Taylor's generalized Ihara lemma for definite unitary groups

About 1 year old · traced to

Let F+\mathsf{F}^+ be a totally real number field, let F/F+\mathsf{F}/\mathsf{F}^+ be a quadratic CM extension containing an imaginary quadratic field K\mathsf{K}, and let G\mathsf{G} be the unitary similitude group associated to a division algebra with involution as in the setup. At a prime pp split in K\mathsf{K}, choose a place vv of F\mathsf{F} above a fixed place ℘\wp of K\mathsf{K} above pp, with the division algebra split at vv. Let KvK^v and A(Kv)\mathcal{A}(K^v) be as defined above, let Λ=F‾ℓ\Lambda=\overline{\mathbb{F}}_\ell for ℓ≠p\ell\neq p, and let TS\mathbb{T}^S be the global Hecke algebra. An irreducible GLn(Fv)\mathrm{GL}_n(\mathsf{F}_v)-representation over Λ\Lambda is Whittaker-generic if it admits nonzero Whittaker coefficients. Let m⊆TS\mathfrak{m}\subseteq\mathbb{T}^S be a non-Eisenstein maximal ideal with A(Kv)m≠0\mathcal{A}(K^v)_\mathfrak{m}\neq 0, and let V⊆A(Kv)mV\subseteq\mathcal{A}(K^v)_\mathfrak{m} be an irreducible GLn(Fv)\mathrm{GL}_n(\mathsf{F}_v)-submodule.

Clozel–Harris–Taylor's generalized Ihara lemma. Then VV is Whittaker-generic.

This is the generalized Ihara lemma proposed by Clozel, Harris, and Taylor for higher-dimensional unitary groups. The supplied material does not state whether this formulation has been proved or remains open.

References

Primary source

Xiangqian Yang, “On Ihara's lemma for definite unitary groups”, arXiv:2504.07504 (2025).

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.