English

Pro-representability of Chow groups and Hodge numbers

Algebraic Geometry 2026-01-05 v1

Abstract

Let kk be an algebraic field extension of Q\mathbb{Q} and let XX be a smooth projective variety over kk of dimension d2d \geq 2. We study the pro-representability of the Chow group CHp(X)CH^{p}(X) with 2pd2 \leq p \leq d. When certain Hodge numbers of XX vanish, namely, Hp(X,ΩX/ki)=Hp+1(X,ΩX/ki)==H2p1i(X,ΩX/ki)=0H^{p}(X,\Omega^{i}_{X/k})=H^{p+1}(X,\Omega^{i}_{X/k})= \cdots =H^{2p-1-i}(X,\Omega^{i}_{X/k})=0 for ii such that 0ip20 \leq i \leq p-2, we prove that the formal completion CH^p(A)\widehat{CH}^{p}(A) of CHp(X)CH^{p}(X) at a local augmented Artinian kk-algebra AA with the maximal ideal mAm_{A} satisfies 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 provides a unified cohomological criterion for the pro-representability of the functor CH^p\widehat{CH}^{p}, generalizing earlier work by Bloch, Stienstra, and Mackall for p=2p=2 and p=3p=3. Our result reveals an intrinsic connection between the deformation theory of algebraic cycles and the Hodge structure of XX.

Keywords

Cite

@article{arxiv.2601.00390,
  title  = {Pro-representability of Chow groups and Hodge numbers},
  author = {Sen Yang},
  journal= {arXiv preprint arXiv:2601.00390},
  year   = {2026}
}