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Tori whose covering spaces have convex distance functions - MaRDI portal

Tori whose covering spaces have convex distance functions (Q1099825)

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scientific article; zbMATH DE number 4042782
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Tori whose covering spaces have convex distance functions
scientific article; zbMATH DE number 4042782

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    Tori whose covering spaces have convex distance functions (English)
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    1986
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    The well known theorem of Hopf, that a 2-dimensional Riemannian torus without conjugate points is flat, does not have a direct analogue for G- spaces, as Busemann has shown. A related hypothesis is given here which does allow an analogue. Namely, if a G-space is homeomorphic to a 2- dimensional torus and its universal covering space M has a point from which the distance function is convex, then M is Minkowskian.
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    convexity
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    theorem of Hopf
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    conjugate points
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    G-spaces
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    torus
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