The lower mean curvature bound in Gromov's mean-of-the-mean-curvature conjecture
Abstract
Gromov conjectured that for a compact Riemannian manifold X with boundary, the total mean curvature ∫∂ X H is bounded above by a constant depending only on the intrinsic geometry of ∂ X and a lower bound on the scalar curvature of X. Previous results towards this conjecture require, in addition, a lower bound on the mean curvature of the boundary. In the present paper, we investigate whether this extra assumption is necessary. In dimension $2$, we show that no lower bound on the geodesic curvature is needed. We estimate the total geodesic curvature of the boundary in terms of its length and a lower bound for the Gauss curvature of the surface. This confirms Gromov's conjecture in $2$~dimensions without any extra assumptions. In contrast, we give examples showing that a lower bound on the mean curvature is genuinely needed in dimensions n ≥ 3.
Related
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BibTeX
@misc{baer2026lower,
title = {{The lower mean curvature bound in Gromov's mean-of-the-mean-curvature conjecture}},
author = {Christian Baer},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01189},
eprint = {2609.01189},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01189},
}
RIS
TY - UNPB
TI - The lower mean curvature bound in Gromov's mean-of-the-mean-curvature conjecture
AU - Christian Baer
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.01189
UR - https://arxiv.org/abs/2609.01189
AB - Gromov conjectured that for a compact Riemannian manifold X with boundary, the total mean curvature ∫_∂ X H is bounded above by a constant depending only on the intrinsic geometry of ∂ X and a lower bound on the scalar curvature of X. Previous results towards this conjecture require, in addition, a lower bound on the mean curvature of the boundary. In the present paper, we investigate whether this extra assumption is necessary. In dimension $2$, we show that no lower bound on the geodesic curvature is needed. We estimate the total geodesic curvature of the boundary in terms of its length and a lower bound for the Gauss curvature of the surface. This confirms Gromov's conjecture in $2$~dimensions without any extra assumptions. In contrast, we give examples showing that a lower bound on the mean curvature is genuinely needed in dimensions n ≥ 3.
ER -