We show how some results of the theory of iterated function systems can be derived from the Tarski–Kantorovitch fixed–point principle for maps on partially ordered sets. In particular, this principle yields, without using the Hausdorff metric, the Hutchinson–Barnsley theorem with the only restriction that a metric space considered has the Heine–Borel property. As a by–product, we also obtain so...

In this paper, some further results on the stability of Ky Fan's points are proposed by introducing a type of stronger perturbation of section mappings defined by a semi-metric called the maximum Hausdorff semi-metric, and the existence of the essential components of the set of Ky Fan's points to this perturbation is proved. As an application, the existence of the essential component of the Nas...

We introduce the concept of effective dimension for a general metric space. Effective dimension was defined by Lutz in (Lutz 2003) for Cantor space and has also been extended to Euclidean space. Our extension to other metric spaces is based on a supergale characterization of Hausdorff dimension. We present here the concept of constructive dimension and its characterization in terms of Kolmogoro...

Given a compact metric space (Ω, d) equipped with a non-atomic, probability measure m and a real, positive decreasing function ψ we consider a ‘natural’ class of lim sup subsets Λ(ψ) of Ω. The classical lim sup sets of ‘well approximable’ numbers in the theory of metric Diophantine approximation fall within this class. We show that m(Λ(ψ)) > 0 under a ‘global ubiquity’ hypothesis and the diverg...

We prove an approximation result for Lipschitz functions on the quantum sphere $S_q^2$, from which we deduce that two natural metric structures $S_q^2$ have Gromov-Hausdorff distance zero.

The purpose of this article is to propose a unified theory for topologies on the closed subsets of a metrizable space. It can be shown that all of the standard hyperspace topologies—including the Hausdorff metric topology, the Vietoris topology, the Attouch-Wets topology, the Fell topology, the locally finite topology, and the topology of Mosco convergence—arise as weak topologies generated by ...

Compact sets in constructive mathematics capture our intuition of what computable subsets of the plane (or any other complete metric space) ought to be. A good representation of compact sets provides an efficient means of creating and displaying images with a computer. In this paper, I build upon existing work about complete metric spaces to define compact sets as the completion of the space of...

The Hausdorff distance, the Gromov-Hausdorff, the Fréchet and the natural pseudo-distances are instances of dissimilarity measures widely used in shape comparison. We show that they share the property of being defined as infρ F (ρ) where F is a suitable functional and ρ varies in a set of correspondences containing the set of homeomorphisms. Our main result states that the set of homeomorphisms...

and Applied Analysis 3 2. Preliminaries In this section, we complete notations and recall some known definitions. Let K X be the class of all nonempty and compact subset of X. If A ∈ K X we define the ε-neighbourhood of A as the set N A, ε {x ∈ X | d x,A < ε}, 2.1 where d x,A infa∈A‖x − a‖. The Hausdorff separation ρ A,B of A,B ∈ K X is defined by ρ A,B inf{ε > 0 | A ⊆ N B, ε }. 2.2 The Hausdor...