The local rigid-inner-form packet conjecture

Let FvF_v be a local completion of the global function field FF, let GG be a connected reductive group over FvF_v, and let WFvW_{F_v}' be the Weil–Deligne group. For a tempered LL-parameter

φv ⁣:WFv\prescriptLG,\varphi_v\colon W_{F_v}'\to\prescript{L}{}G,

write Πtemprig(G)\Pi_{\mathrm{temp}}^{\mathrm{rig}}(G) for the set of tempered representations of rigid inner forms of GG, Sφv+S_{\varphi_v}^{+} for the relevant parameter centralizer, and Ev\mathcal{E}_v for the local gerbe defining rigid inner twists. The local rigid-inner-form packet conjecture. There is a finite subset ΠφvΠtemprig(G)\Pi_{\varphi_v}\subset\Pi_{\mathrm{temp}}^{\mathrm{rig}}(G) and a commutative diagram

\begin{tikzcd} \Pi_{\varphi_v} \arrow["\iota_{\varphi_v,\mathfrak{w}_v}"]{r} \arrow{d} & \operatorname{Irr}(\pi_0(S_{\varphi_v}^{+})) \arrow{d} \\ H^{1}(\mathcal{E}_v,Z\to G^{*}) \arrow{r} & \pi_0(Z(\widehat{\overline{G}})^{+,v})^{*}, \end{tikzcd}

where GG^{*} is the quasi-split inner form and ZZ is the chosen finite central subgroup. This is the predicted local Langlands-packet structure for rigid inner forms; the source presents it as part of the conjectural framework, and no resolution status is supplied.

Sources & referencesView supporting material

Primary source

Peter Dillery, “Rigid inner forms over global function fields”, arXiv:2110.10820 (2025).

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