Abstract
We prove that the unit tangent sphere bundle of a Riemannian manifold is semi-symmetric if and only if it is locally symmetric, i.e., the base manifold is either flat or it is two-dimensional with constant sectional curvature 1.
Citation
Eric Boeckx. Giovanni Calvaruso. "When is the unit tangent sphere bundle semi-symmetric?." Tohoku Math. J. (2) 56 (3) 357 - 366, 2004. https://doi.org/10.2748/tmj/1113246672
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