Kobayashi's pseudo-Riemannian space-form conjecture

Let a pseudo-Riemannian space form of signature (p,q)(p,q) be a pseudo-Riemannian manifold with constant sectional curvature κ\kappa, where p,q0p,q\neq 0. Kobayashi's pseudo-Riemannian space-form conjecture. There exists a compact space form with signature (p,q)(p,q) and sectional curvature κ\kappa if and only if one of the following holds: κ<0\kappa<0 and (p,q)(p,q) is one of (1,2n)(1,2n), (3,4n)(3,4n), or (7,8)(7,8); κ=0\kappa=0 and (p,q)(p,q) is arbitrary; or κ>0\kappa>0 and (p,q)(p,q) is one of (2n,1)(2n,1), (4n,3)(4n,3), or (8,7)(8,7). This conjecture proposes a precise classification of compact pseudo-Riemannian space forms by signature and curvature; the supplied text does not indicate that it has been resolved.

Sources & referencesView supporting material

Primary source

David Constantine, “Compact Clifford-Klein forms – geometry, topology and dynamics”, arXiv:1307.2183 (2013).

Additional references

2 papers in this index state this conjecture (2005–2013). The statement above is taken from the most recent of them; the others are arXiv:math/0509543.

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