PreprintCC BY-SA 4.0arXiv
Positive biorthogonal curvature on S2× T2
Abstract
We construct explicit Riemannian metrics with positive biorthogonal curvature on S2× T2, answering a question of Bettiol. In particular, positive biorthogonal curvature on a closed four-manifold does not force its fundamental group to be virtually free.
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BibTeX
@misc{chen2026positive,
title = {{Positive biorthogonal curvature on $S^2\times T^2$}},
author = {Zhiqi Chen and Hui Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.08119},
eprint = {2609.08119},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.08119},
note = {CC BY-SA 4.0},
}
RIS
TY - UNPB
TI - Positive biorthogonal curvature on S^2× T^2
AU - Zhiqi Chen
AU - Hui Zhang
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2609.08119
UR - https://arxiv.org/abs/2609.08119
AB - We construct explicit Riemannian metrics with positive biorthogonal curvature on S^2× T^2, answering a question of Bettiol. In particular, positive biorthogonal curvature on a closed four-manifold does not force its fundamental group to be virtually free.
ER -