PreprintCC BY 4.0arXiv
Witt groups of smooth real curves and surfaces
Abstract
We study the I*-cohomology of a smooth real algebraic curve in terms of its real locus and its geometric genus. We notably extend results of Monnier to the twisted case, which is crucial to the understanding of proper pushforwards of Witt groups. We also perform some computations related to transfers along the finite étale extension ℂ/ℝ. We further describe how to compute twisted Witt groups of surfaces, extending work of Sujatha, and the image of the global signature homomorphism following Monnier. As an application of the main methods of the paper, we describe the shifted and twisted Witt groups of smooth anisotropic quadrics over ℝ of dimension ≤ 3.
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BibTeX
@misc{lerbet2026witt,
title = {{Witt groups of smooth real curves and surfaces}},
author = {Samuel Lerbet},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.18599},
eprint = {2608.18599},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.18599},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Witt groups of smooth real curves and surfaces
AU - Samuel Lerbet
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2608.18599
UR - https://arxiv.org/abs/2608.18599
AB - We study the I^*-cohomology of a smooth real algebraic curve in terms of its real locus and its geometric genus. We notably extend results of Monnier to the twisted case, which is crucial to the understanding of proper pushforwards of Witt groups. We also perform some computations related to transfers along the finite étale extension ℂ/ℝ. We further describe how to compute twisted Witt groups of surfaces, extending work of Sujatha, and the image of the global signature homomorphism following Monnier. As an application of the main methods of the paper, we describe the shifted and twisted Witt groups of smooth anisotropic quadrics over ℝ of dimension ≤ 3.
ER -