English

Absolutely special subvarieties and absolute Hodge cycles

Algebraic Geometry 2022-05-30 v2 Number Theory

Abstract

We introduce the notion of dR-absolutely special subvarieties in motivic variations of Hodge structure as special subvarieties cut out by (de Rham-)absolute Hodge cycles and conjecture that all special subvarieties are dR-absolutely special. This is implied by Deligne's conjecture that all Hodge cycles are absolute Hodge cycles, but is a much weaker conjecture. We prove our conjecture for subvarieties satisfying a simple monodromy condition introduced by Klingler-Otwinowska-Urbanik. We study applications to typical respectively atypical intersections and Qˉ\bar{\mathbb{Q}}-bialgebraic subvarieties. Finally, we show that Deligne's conjecture as well as ours can be reduced to the case of special points in motivic variations.

Keywords

Cite

@article{arxiv.2111.00216,
  title  = {Absolutely special subvarieties and absolute Hodge cycles},
  author = {Tobias Kreutz},
  journal= {arXiv preprint arXiv:2111.00216},
  year   = {2022}
}

Comments

minor improvements, comments welcome!

R2 v1 2026-06-24T07:18:56.492Z