Tate conjecture in characteristic p for integral Shimura models

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Let k(v)k(v) be the residue field at vv, let κ\kappa be a perfect field over k(v)k(v), and let x∈SK(κ)x\in \mathscr{S}_K(\kappa). For each prime ℓ\ell, write Iℓ,xI_{\ell,x} for the corresponding realization group, and let Aut⁡p(x)\operatorname{Aut}^p(x) denote the prime-to-pp automorphism group appearing in the realization construction. Tate conjecture in characteristic pp. There exists a reductive group IxI_x over Q\mathbb{Q} with realization maps

αℓ ⁣:Ix⊗QQℓ→Iℓ,x\alpha_\ell\colon I_x\otimes_{\mathbb{Q}}\mathbb{Q}_\ell\to I_{\ell,x}

for all primes ℓ\ell, satisfying

Ix(Z(p))=Ix(Q)∩IZp,x(Zp)=Aut⁡p(x),I_x(\mathbb{Z}_{(p)})=I_x(\mathbb{Q})\cap I_{\mathbb{Z}_p,x}(\mathbb{Z}_p)=\operatorname{Aut}^p(x),

and such that the map Ix(Z(p))→Iℓ,x(Qℓ)I_x(\mathbb{Z}_{(p)})\to I_{\ell,x}(\mathbb{Q}_\ell) is the realization map from the cited quasi-isogeny construction. If κ\kappa is finite, then for every prime ℓ\ell the realization map

Ix⊗QQℓ→Iℓ,xI_x\otimes_{\mathbb{Q}}\mathbb{Q}_\ell\to I_{\ell,x}

is an isomorphism. This is the characteristic-pp analogue of the preceding Tate conjecture, combining the integral prime-to-pp realization property with the asserted isomorphism over finite fields. The source provides no evidence resolving it.

References

Primary source

Keerthi Madapusi and Alex Youcis, “On canonicity for integral models of Shimura varieties with hyperspecial level”, arXiv:2604.06442 (2026).

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