Invariant approximations for commuting mappings in CAT(0) and hyperconvex spaces

摘要

In this paper, for a commuting pair consisting of a point-valued nonexpansive self-mapping t and a set-valued nonexpansive self-mapping T of a hyperconvex metric space (or a CAT(0) space) X, we look for a solution to the problem of existence of z is an element of E subset of X such that d(z,y)=d(y,E) and z=t(z)is an element of T(z). (C) 2007 Elsevier Inc. All rights reserved.