Let G be a covering group with subgroup G0, let G†=Z(G)⋅G0, and let ϕπ be an L-parameter of G. Write ϕπ♢=fG,H∘ϕπ and let Φ(LG0;ϕπ) be the set of parameters ϕ0 satisfying fG0,H∘ϕ0=ϕπ♢. For enhanced parameters (ϕ,θ), write Sϕ for the component group and use the embeddings into Sϕπ♢. Let π∈Irrgen(G) have central character ωπ and enhanced parameter (ϕπ,θπ), and let τ⊠ρ be an irreducible constituent of π∣G†. Restriction and induction compatibility conjecture. (i) The parameters satisfy fG,z∘ϕπ=fc,z∘ϕτ=ϕωπ and ϕπ♢=fG0,H∘ϕρ. (ii) There exists e(π)∈N such that for every τ∈Irrgen(G0) with enhanced parameter (ϕτ,θτ),
In the isotypic case, the stated direct-sum formula for π∣G0 holds. (iii) Compatible τ∈Irrgen(Z(G)) and ρ∈Irrgen(G0) induce constituents whose parameters fit into the specified commutative L-group diagram. This conjectural package predicts compatibility of enhanced local Langlands parameters with central characters, restriction, and induction.
References
Primary source
Fan Gao, Freydoon Shahidi and Dani Szpruch, “Restrictions, L-parameters, and local coefficients for genuine representations”, arXiv:2102.08859 (2021).