A surface with representable $\text{CH}_{0}$-group but no universal zero-cycle

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1. Verfasser: Alexandrou, Theodosis
Format: Preprint
Veröffentlicht: 2026
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author Alexandrou, Theodosis
author_facet Alexandrou, Theodosis
contents We introduce a new obstruction to the existence of a universal $0$-cycle on a smooth projective complex variety. As an application, we construct a smooth projective complex surface whose Chow group of $0$-cycles is representable but which does not admit a universal $0$-cycle. This provides a two-dimensional analogue of Voisin's recent threefold counterexample to a question of Colliot-Thélène. As a further consequence, we exhibit the first example of a smooth projective threefold of Kodaira dimension zero carrying a non-torsion Hodge class of degree $4$ that is not algebraic. The construction relies on the geometry of bielliptic surfaces of type 2.
format Preprint
id arxiv_https___arxiv_org_abs_2602_13435
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A surface with representable $\text{CH}_{0}$-group but no universal zero-cycle
Alexandrou, Theodosis
Algebraic Geometry
K-Theory and Homology
14C25 (Primary) 14C30, 14J27 (Secondary)
We introduce a new obstruction to the existence of a universal $0$-cycle on a smooth projective complex variety. As an application, we construct a smooth projective complex surface whose Chow group of $0$-cycles is representable but which does not admit a universal $0$-cycle. This provides a two-dimensional analogue of Voisin's recent threefold counterexample to a question of Colliot-Thélène. As a further consequence, we exhibit the first example of a smooth projective threefold of Kodaira dimension zero carrying a non-torsion Hodge class of degree $4$ that is not algebraic. The construction relies on the geometry of bielliptic surfaces of type 2.
title A surface with representable $\text{CH}_{0}$-group but no universal zero-cycle
topic Algebraic Geometry
K-Theory and Homology
14C25 (Primary) 14C30, 14J27 (Secondary)
url https://arxiv.org/abs/2602.13435