On the topology of closed manifolds with quasi-constant sectional curvature
Louis Funar
Journal de l'École polytechnique — Mathématiques, Volume 6 (2019), p. 365-421

We prove that closed manifolds admitting a generic metric whose sectional curvature is locally quasi-constant are graphs of space forms. In the more general setting of QC spaces where sets of isotropic points are arbitrary, under suitable positivity assumption and for torsion-free fundamental groups, they are still diffeomorphic to connected sums of spherical bundles over the circle.

Nous montrons que les variétés fermées admettant une métrique générique dont la courbure sectionnelle est localement quasi-constante sont des sommes graphées de variétés de courbure constante. Ensuite nous étendons ce résultat au cas des espaces QC dont l’ensemble des points isotropes pourrait être arbitraire en démontrant que, sous une condition de positivité et lorsque leurs groupes fondamentaux sont sans torsion, ils sont difféomorphes à des sommes connexes de fibrés en sphères sur le cercle.

Received : 2017-07-10
Accepted : 2019-05-29
Published online : 2019-06-12
DOI : https://doi.org/10.5802/jep.96
Classification:  53C21,  53C23,  53C25,  57R42
Keywords: Curvature, conformal geometry, topology, curvature leaves, codimension-one isometric immersions, foliations, second fundamental form
@article{JEP_2019__6__365_0,
     author = {Louis Funar},
     title = {On the topology of closed manifolds with quasi-constant sectional curvature},
     journal = {Journal de l'\'Ecole polytechnique --- Math\'ematiques},
     publisher = {\'Ecole polytechnique},
     volume = {6},
     year = {2019},
     pages = {365-421},
     doi = {10.5802/jep.96},
     language = {en},
     url = {https://jep.centre-mersenne.org/item/JEP_2019__6__365_0}
}
On the topology of closed manifolds with quasi-constant sectional curvature. Journal de l'École polytechnique — Mathématiques, Volume 6 (2019) pp. 365-421. doi : 10.5802/jep.96. https://jep.centre-mersenne.org/item/JEP_2019__6__365_0/

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