English

New counterexamples to the birational Torelli theorem for Calabi--Yau manifolds

Algebraic Geometry 2022-11-08 v1

Abstract

We produce counterexamples to the birational Torelli theorem for Calabi-Yau manifolds in arbitrarily high dimension: this is done by exhibiting a series of non birational pairs of Calabi-Yau (n21)(n^2-1)-folds which, for n2n \geq 2 even, admit an isometry between their middle cohomologies. These varieties also satisfy an L\mathbb L-equivalence relation in the Grothendieck ring of varieties, i.e. the difference of their classes annihilates a power of the class of the affine line. We state this last property for a broader class of Calabi-Yau pairs, namely all those which are realized as pushforwards of a general (1,1)(1,1)-section on a homogeneous roof in the sense of Kanemitsu, along its two extremal contractions.

Keywords

Cite

@article{arxiv.2211.03702,
  title  = {New counterexamples to the birational Torelli theorem for Calabi--Yau manifolds},
  author = {Marco Rampazzo},
  journal= {arXiv preprint arXiv:2211.03702},
  year   = {2022}
}

Comments

17 pages, comments are welcome!