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Petra Weidner - One of the best experts on this subject based on the ideXlab platform.

I. Namioka - One of the best experts on this subject based on the ideXlab platform.

  • Kakutani-type fixed point theorems: A survey
    Journal of Fixed Point Theory and Applications, 2011
    Co-Authors: I. Namioka
    Abstract:

    A Kakutani-type fixed point theorem refers to a theorem of the following kind: Given a group or semigroup S of continuous affine transformations s : Q → Q , where Q is a nonempty compact convex subset of a Hausdorff locally convex Linear Topological Space, then under suitable conditions S has a common fixed point in Q , i.e., a point $${a \in Q}$$ such that s ( a ) = a for each $${s \in S}$$ . In 1938, Kakutani gave two conditions under each of which a common fixed point of S in Q exists. They are (1) the condition that S be a commutative semigroup, and (2) the condition that S be an equicontinuous group. The present survey discusses subsequent generalizations of Kakutani’s two theorems above.

Jian Zhong Xiao - One of the best experts on this subject based on the ideXlab platform.

  • Topological degree theory and fixed point theorems in fuzzy normed Space
    Fuzzy Sets and Systems, 2004
    Co-Authors: Jian Zhong Xiao
    Abstract:

    Abstract In this paper, the Leray–Schauder Topological degree theory is developed in a fuzzy normed Space. Since the Linear topology on this fuzzy normed Space is not necessarily locally convex, and since each Menger probabilistic normed Space can be considered as a special fuzzy normed Space, the degree theory in this paper is different from the degree theory in locally convex Linear Topological Space presented by Nagumo (Amer. J. Math. 73 (1951) 497–511), and it also is an extension of the degree theory in Menger probabilistic normed Space studied by Zhang and Chen (Appl. Math. Mech. 10(6) (1989) 477–486). Applying this degree theory, some fixed point theorems for operators are given in fuzzy normed Spaces, and some former corresponding results are extended and improved.

Liu Xiu-hong - One of the best experts on this subject based on the ideXlab platform.

Liu Jim - One of the best experts on this subject based on the ideXlab platform.