Kobayashi's conjecture on fundamental groups of positively curved semi-Riemannian manifolds
Kobayashi's conjecture on fundamental groups of positively curved semi-Riemannian manifolds
Let and be positive integers with . Let be an -dimensional geodesically complete semi-Riemannian manifold of index , and suppose its sectional curvature has a positive lower bound. Kobayashi's conjecture. The manifold is never compact, and, if , its fundamental group is finite. The conjecture is presented as a perturbative analogue of the Calabi–Markus–Wolf finiteness theorem for positive constant curvature; the supplied text also says that it is true by Kulkarni's theorem, which reduces the one-sided sectional-curvature bound to constant curvature.
Sources & referencesView supporting material
Primary source
Jun-ichi Mukuno, “On the fundamental group of semi-Riemannian manifolds with positive curvature tensor”, arXiv:1704.04944 (2021).
Additional references
2 papers in this index state this conjecture (2014–2017). The statement above is taken from the most recent of them; the others are arXiv:1409.0957.
Progress summary
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