We give a generalization of the classical Helly's theorem on intersection of convex sets in RN\mathbb{R}^N for the case of manifolds of nonpositive curvature. In particular, we show that if any N+1 sets from a family of closed convex sets on N-dimensional Cartan-Hadamard manifold contain a common point, then all sets from this family contain a common point

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Yuri S. Ledyaev

Dept. of Mathematics, Western Michigan University, Kalamazoo, MI 49008, U.S.A.
Permanent Address: Steklov Institute of Mathematics, 117966 Moscow, Russia

ledyaev@wmich.edu

Jay S. Treiman

Dept. of Mathematics, Western Michigan University, Kalamazoo, MI 49008, U.S.A.

jay.treiman@wmich.edu

Qiji J. Zhu

Dept. of Mathematics, Western Michigan University, Kalamazoo, MI 49008, U.S.A.

qiji.zhu@wmich.edu
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Y. S. Ledyaev, J. S. Treiman, Q. J. Zhu. “Helly's Intersection Theorem on Manifolds of Nonpositive Curvature.” Journal of Convex Analysis 13 (2006), No. 3/4, 785–798. https://doi.org/10.68381/jca13059