We introduce the notion of a generalized iterated function system (GIFS), which is a finite family of functions , where is a metric space and . In case that is a compact metric space and the functions are contractions, using some fixed point theorems for contractions from to , we prove the existence of the attractor of such a GIFS and its continuous dependence in the 's.
21 January 2010 in Fixed Point Theory and Applications
The aim of this paper is to continue the research work that we have done in a previous paper published in this journal (see Mihail and Miculescu, 2008). We introduce the notion of GIFS, which is a family of functions "Equation missing"<!-- image only, no MathML or LaTex -->, where "Equation missing"<!-- image only, no MathML or LaTex --> is a complete metric space (in the above mentioned paper the case when "Equation missing"<!-- image only, no MathML or LaTex --> is a compact metric space was studied) and "Equation missing"<!-- image only, no MathML or LaTex -->. In case that the functions "Equation missing"<!-- image only, no MathML or LaTex --> are Lipschitz contractions, we prove the existence of the attractor of such a GIFS and explore its properties (among them we give an upper bound for the Hausdorff-Pompeiu distance between the attractors of two such GIFSs, an upper bound for the Hausdorff-Pompeiu distance between the attractor of such a GIFS, and an arbitrary compact set of "Equation missing"<!-- image only, no MathML or LaTex --> and we prove its continuous dependence in the "Equation missing"<!-- image only, no MathML or LaTex -->'s). Finally we present some examples of attractors of GIFSs. The last example shows that the notion of GIFS is a natural generalization of the notion of IFS.
Georganopoulos (see [1] ) has shown that a continuous function f : X → B, where X is a compact metric space and B a convex subset of a real normed space Y, is the uniform limit of a sequence of Lipschitz maps from X to B. In this note we obtain a similar result, namely we show that a continuous function f : X → ℝ, where X is a metric space, is a uniform limit of a sequence of locally Lipschitz maps from X to ℝ. When X is compact and B = Y = ℝ, we get the Georganopoulos' result.
26 September 2015 in Journal of Fixed Point Theory and Applications