Download PDF - Hyperconvexity of ℝ-trees
ArticleOriginal scientific text
Title
Hyperconvexity of ℝ-trees
Authors 1
Affiliations
- Department of Mathematics, University of Iowa, Iowa City, Iowa 52242-1419, U.S.A.
Abstract
It is shown that for a metric space (M,d) the following are equivalent: (i) M is a complete ℝ-tree; (ii) M is hyperconvex and has unique metric segments.
Keywords
hyperconvex metric space, ℝ-tree, fixed point, nonexpansive mapping
Bibliography
- N. Aronszajn and P. Panitchpakdi, Extensions of uniformly continuous transformations and hyperconvex metric spaces, Pacific J. Math. 6 (1956), 405-439.
- J. B. Baillon, Nonexpansive mappings and hyperconvex spaces, in: Fixed Point Theory and its Applications, R. F. Brown (ed.), Contemp. Math. 72, Amer. Math. Soc., Providence, R.I., 1988, 11-19.
- L. M. Blumenthal, Distance Geometry, Oxford Univ. Press, London, 1953.
- J. R. Isbell, Six theorems about injective metric spaces, Comment. Math. Helv. 39 (1964), 439-447.
- E. Jawhari, D. Misane and M. Pouzet, Retracts: graphs and ordered sets from the metric point of view, in: Combinatorics and Ordered Graphs, I. Rival (ed.), Contemp. Math. 57, Amer. Math. Soc., Providence, R.I., 1986, 175-226.
- M. A. Khamsi, On metric spaces with uniform normal structure, Proc. Amer. Math. Soc. 106 (1989), 723-726.
- M. A. Khamsi, KKM and Ky Fan theorems in hyperconvex metric spaces, J. Math. Anal. Appl. 204 (1996), 298-306.
- W. A. Kirk and S. S. Shin, Fixed point theorems in hyperconvex spaces, Houston J. Math. 23 (1997), 175-188.
- J. Kulesza and T. C. Lim, On weak compactness and countable weak compactness in fixed point theory, Proc. Amer. Math. Soc. 124 (1996), 3345-3349.
- H. E. Lacey, The Isometric Theory of Classical Banach Spaces, Springer, Berlin, 1974.
- R. Mańka, Association and fixed points, Fund. Math. 91 (1976), 105-121.
- J. W. Morgan, Λ-trees and their applications, Bull. Amer. Math. Soc. 26 (1992), 87-112.
- F. Rimlinger, Free actions on ℝ-trees, Trans. Amer. Math. Soc. 332 (1992), 313-329.
- R. Sine, On nonlinear contractions in sup norm spaces, Nonlinear Anal. 3 (1979), 885-890.
- P. Soardi, Existence of fixed points of nonexpansive mappings in certain Banach lattices, Proc. Amer. Math. Soc. 73 (1979), 25-29.
- F. Sullivan, Ordering and completeness of metric spaces, Nieuw Arch. Wisk. (3) 29 (1981), 178-193.
- J. Tits, A "Theorem of Lie-Kolchin" for trees, in: Contributions to Algebra: a Collection of Papers Dedicated to Ellis Kolchin, Academic Press, New York, 1977, 377-388.