English

Deformations of Chow groups via cyclic homology

Algebraic Geometry 2026-01-16 v1

Abstract

Let XX be a smooth projective variety over an arbitrary field kk of characteristic zero. We explore infinitesimal deformations of the Chow group CHp(X)CH^{p}(X) via its formal completion CH^p\widehat{CH}^{p}, a functor defined on the category of local augmented Artinian kk-algebras. Under a natural vanishing condition on Hodge cohomology groups, for certain augmented graded Artinian kk-algebras AA with the maximal ideal mAm_{A}, we prove that CH^p(A)Hp(X,ΩX/kp1)kmA. \widehat{CH}^{p}(A) \cong H^{p}(X, \Omega^{p-1}_{X/ k})\otimes_{k}m_{A}. This extends earlier results of Bloch and others from the case where kk is algebraic over Q\mathbb{Q} to arbitrary fields of characteristic zero,and gives a partial affirmative answer to a general question linking the pro-representability of Chow groups to a specific set of Hodge-theoretic vanishing conditions.

Keywords

Cite

@article{arxiv.2601.10309,
  title  = {Deformations of Chow groups via cyclic homology},
  author = {Sen Yang},
  journal= {arXiv preprint arXiv:2601.10309},
  year   = {2026}
}