Variational filtered log p-adic hard Lefschetz conjecture

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Let X/S0X/S_0 be a proper SNCL scheme with structural morphism f ⁣:X⟶S0⟶⊂Sf\colon X\longrightarrow S_0\overset{\subset}{\longrightarrow} S, and suppose that the relative dimension of X∘⟶S∘0\overset{\circ}{X}\longrightarrow\overset{\circ}{S}_0 is pure of dimension dd. Let LL be a relatively ample line bundle on X∘/S∘0\overset{\circ}{X}/\overset{\circ}{S}_0, and let η=c1,crys⁡(L)\eta=c_{1,\operatorname{crys}}(L) be its Chern class in R2fX/S∗(OX/S)R^2f_{X/S*}({\cal O}_{X/S}). Write PP for the weight filtration. Variational filtered log pp-adic hard Lefschetz conjecture. For every ii, the cup product

ηi ⁣:Rd−ifX/S∗(OX/S)⊗ZQ⟶Rd+ifX/S∗(OX/S)⊗ZQ\eta^i\colon R^{d-i}f_{X/S*}({\cal O}_{X/S})\otimes_{\mathbb Z}{\mathbb Q}\longrightarrow R^{d+i}f_{X/S*}({\cal O}_{X/S})\otimes_{\mathbb Z}{\mathbb Q}

is an isomorphism. In fact, it should be an isomorphism of filtered sheaves

ηi ⁣:(Rd−ifX/S∗(OX/S)⊗ZQ,P)⟶∼((Rd+ifX/S∗(OX/S)⊗ZQ)(i),P),\eta^i\colon (R^{d-i}f_{X/S*}({\cal O}_{X/S})\otimes_{\mathbb Z}{\mathbb Q},P)\overset{\sim}{\longrightarrow}((R^{d+i}f_{X/S*}({\cal O}_{X/S})\otimes_{\mathbb Z}{\mathbb Q})(i),P),

where

Pk(Rd+ifX/S∗(OX/S)⊗ZQ)(i))=Pk+2iRd+ifX/S∗(OX/S)⊗ZQ.P_k(R^{d+i}f_{X/S*}({\cal O}_{X/S})\otimes_{\mathbb Z}{\mathbb Q})(i))=P_{k+2i}R^{d+i}f_{X/S*}({\cal O}_{X/S})\otimes_{\mathbb Z}{\mathbb Q}.

This is a filtered, relative logarithmic crystalline analogue of the hard Lefschetz theorem. The supplied text attributes the conjecture to the author's earlier work and gives no evidence that it has been resolved.

References

Primary source

Yukiyoshi Nakkajima, “Hirsch weight-filtered log crystalline complex and Hirsch weight-filtered log crystalline dga of a proper SNCL scheme in characteristic p>0”, arXiv:2012.12981 (2025).

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