The local integral-model conjecture for Γ1(p)\Gamma_1(p)-level local Shimura varieties

Let (G,{μ},b)(G,\{\mu\},b) be a local Shimura datum, let G{\mathcal G} be parahoric, set K0=G(Zp)K_0={\mathcal G}(\mathbb Z_p), and let K1K_1 be the kernel of the reduction map to the reductive abelian quotient over Fp\mathbb F_p. Choose SSG,μX(TG)S\subset S_{{\mathcal G},\mu}\subset X^*(T_{\mathcal G}). The local Γ1(p)\Gamma_1(p)-integral-model conjecture. There exists a formal scheme MK1,S{\mathcal M}^{\rm \int}_{K_1,S} over Spf(OE˘)\operatorname{Spf}(O_{\breve E}) with rigid generic fiber ShtK1(G,μ,b){\rm Sht}_{K_1}(G,\mu,b), together with a morphism to MK0{\mathcal M}^{\rm \int}_{K_0} extending the generic-fiber cover, an extended TG(Fp)T_{\mathcal G}(\mathbb F_p)-action identifying the quotient with MK0{\mathcal M}^{\rm \int}_{K_0}, and a morphism to [G\MG,μS][\mathcal G\backslash{\rm M}^{\sqrt S}_{{\mathcal G},\mu}] fitting into the stated 22-commutative diagram and inducing the stated isomorphism of formal stacks. This is the local analogue of the global conjecture; the local-model map is known in at least the PEL case, but the asserted level-K1K_1 formal model is left conjectural.

Sources & referencesView supporting material

Primary source

Georgios Pappas and Michael Rapoport, “Toric schemes and integral models for Shimura varieties with Γ_1(p)-type level”, arXiv:2602.23245 (2026).

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.