Previous |  Up |  Next

Article

Keywords:
family of sets in general position; convexly connected sets; Fan-Glicksberg-Kakutani fixed point theorem
Summary:
In this paper the main result in [1], concerning $(n+1)$-families of sets in general position in ${\bold R}^n$, is generalized. Finally we prove the following theorem: If $\{A_1,A_2,\dots,A_{n+1}\}$ is a family of compact convexly connected sets in general position in ${\bold R}^n$, then for each proper subset $I$ of $\{1,2,\dots,n+1\}$ the set of hyperplanes separating $\cup\{A_i: i\in I\}$ and $\cup\{A_j: j\in \overline{I}\}$ is homeomorphic to $S_n^+$.
References:
[1] Balaj M.: $(n{+}1)$-families of sets in general position. Beitrage zur Algebra und Geometrie 37 (1996), 67-74. MR 1407806 | Zbl 0856.52007
[2] Fan K.: Fixed-point and minimax theorems in locally convex topological linear spaces. Proc. Nat. Acad. Sci. U.S.A. 38 (1952), 121-126. MR 0047317 | Zbl 0047.35103
[3] Gaal S.A.: Point Set Topology. Academic Press, New York and London, 1964. MR 0171253 | Zbl 0124.15401
[4] Glicksberg I.L.: A further generalization of the Kakutani fixed point theorem, with application to Nash equilibrium points. Proc. Amer. Math. Soc. 3 (1952), 170-174. MR 0046638 | Zbl 0163.38301
[5] Hanner O., Radström H.: A generalization of a theorem of Fenchel. Proc. Amer. Math. Soc. 2 (1951), 589-593. MR 0044142
[6] Singer I.: Best Approximation in Normed Linear Spaces by Elements of Linear Subspaces (in Romanian). Edit. Academiei Române, Bucureşti, 1967. MR 0235368
[7] Valentine F.A.: The dual cone and Helly type theorems. in: Convexity, V.L. Klee ed., Proc. Sympos. Pure Math. 7, Amer. Math. Soc., 1963, pp.473-493. MR 0157285 | Zbl 0138.43204
[8] Valentine F.A.: Konvexe Mengen. Manheim, 1968. MR 0226495 | Zbl 0157.52501
Partner of
EuDML logo