Sharp de Rham realization

Crystalline realizations of 1-motives

We consider the crystalline realization of Deligne's 1-motives in positive characteristics and prove a comparison theorem with the De Rham realization of liftings to zero characteristic. We then show that one dimensional crystalline cohomology of an algebraic variety, defined by universal cohomological descent via de Jong's alterations, coincide with the crystalline realization of the (cohomological) Picard 1-motive, over perfect fields.

Conservativity of realizations implies that numerical motives are Kimura-finite and motivic zeta functions are rational

We prove: if the (étale or de Rham) realization functor is conservative on the category $DM_{gm}$ of Voevodsky motives with rational coefficients then motivic zeta functions of arbitrary varieties are rational and numerical motives are Kimura-finite. The latter statement immediately implies that the category of numerical motives is (essentially) Tannakian. This observation becomes actual due to the recent announcement of J. Ayoub that the De Rham cohomology realization is conservative on $DM_{gm}(k)$ whenever $\operatorname{char} k=0$. We apply this statement to exterior powers of motives comi…

The Monsky-Washnitzer and the overconvergent realizations

We construct the dagger realization functor for analytic motives over non-archimedean fields of mixed characteristic, as well as the Monsky-Washnitzer realization functor for algebraic motives over a discrete field of positive characteristic. In particular, the motivic language on the classic étale site provides a new direct definition of the overconvergent de Rham cohomology and rigid cohomology and shows that their finite dimensionality follows formally from the one of Betti cohomology for smooth projective complex varieties.

Ogus realization of 1-motives

After introducing the Ogus realization of 1-motives we prove that it is a fully faithful functor. More precisely, following a framework introduced by Ogus, considering an enriched structure on the de Rham realization of 1-motives over a number field, we show that it yields a full functor by making use of an algebraicity theorem of Bost.

Réalisations de Hodge des motifs de Voevodsky

Over a subfield of the field of complex numbers, the Hodge realization of a geometrical motive is defined and represented as the cohomology of a mixed Hodge DG-complex in the sense of Deligne. Both filtrations are represented by truncation functors, on a Bondarko weight complex for the weight filtration and on the De Rham motivic complex for the Hodge one. The Deligne-Beilinson realization is also constructed. This preprint partially replaces the former "Réalisation des complexes motiviques de Voevodsky".

Polynomial realizations of period matrices of projective smooth complete intersections and their deformation

Let $X$ be a smooth complete intersection over $\mathbb{C}$ of dimension $n-k$ in the projective space $\mathbf{P}^n_{\mathbb{C}}$, for given positive integers $n$ and $k$. For a given integral homology cycle $[γ] \in H_{n-k}(X(\mathbb{C}),\mathbb{Z})$, the period integral is defined to be a linear map from the de Rham cohomology group to $\mathbb{C}$ given by $[ω] \mapsto \int_γω$. The goal of this article is to interpret this period integral as a linear map from the polynomial ring with $n+k+1$ variables to $\mathbb{C}$ and use this interpretation to develop a deformation theory of period in…

Betti realization of varieties defined by formal Laurent series

We give two constructions of functorial topological realizations for schemes of finite type over the field $\mathbb{C}(\!(t)\!)$ of formal Laurent series with complex coefficients, with values in the homotopy category of spaces over the circle. The problem of constructing such a realization was stated by D. Treumann, motivated by certain questions in mirror symmetry. The first construction uses spreading out and the usual Betti realization over $\mathbb{C}$. The second uses generalized semistable models and log Betti realization defined by Kato and Nakayama, and applies to smooth rigid analyti…

Berkovich 2-动机与规范环堆栈

Berkovich $2$-motives and normed ring stacks

本文提出并证明了动机同调理论核范畴与同调平凡的光滑缝合环堆栈的关系，并探讨了其在分析几何中的应用。

Deligne's conjecture on extensions of 1-motives

We introduce the notion of extension of 1-motives. Using the dictionary between strictly commutative Picard stacks and complexes of abelian sheaves concentrated in degrees -1 and 0, we check that an extension of 1-motives induces an extension of the corresponding strictly commutative Picard stacks. We compute the Hodge, the de Rham and the l-adic realizations of an extention of 1-motives. Using these results we can prove Deligne's conjecture on extensions of 1-motives.

关于dg范畴幻性的一个准则

A Criterion for Phantomness of dg-categories

本文研究了光滑proper dg范畴的幻性是否由加法不变量的消失所刻画，构造了非紧致动机并证明其l-adic实现在代数K-理论中的作用，同时给出了在Chow动机为Kimura有限时幻性的判别准则。

1-动机范畴中晶体类的塔类型定理

Crystalline Realizations of 1-Motives: Integral Structure and Classification via Linear Frobenius

本文在1-动机范围内证明了p进版本的塔猜想，通过Deligne 1-动机的全忠实性定理，将Barsotti-Tate晶体函子与滤过Dieudonné模的Hom群联系起来，从而得出Frobenius兼容的晶体类本质上是动机的，进而给出动机映射的线性代数描述。