Symplectic Geometry has seen a rapid development since the 80's with the discovery of rigidity phenomena like the non-squeezing theorem based on Gromov's seminal theory of pseudo-holomorphic curves. A directly related development was Floer's method of using Morse theory in a new way, known as Floer homology, in order to solve the Arnold conjecture. In the 60's Arnold formulated his conjecture b...

Suucient conditions for controllability of semilinear integrodif-ferential systems in a Banach space are established. The results are obtained using the asymptotic xed-point theorem for k-set contractions .

In this paper we establish existence and regularity of positive solutions for a singular quasilinear elliptic system with competitive structure. The approach is based on comparison properties, a priori estimates and the Schauder’s …xed point theorem.

e study of dynamic equations on time scales goes back to the 1989 Ph.D. thesis of Hilger [1, 2] and is currently an area of mathematics receiving considerable attention [3– 7]. Although the basic aim of the theory of time scales is to unify the study of differential and difference equations in one and the same subject, it also extends these classical domains to hybrid and in-between cases. A g...

Many questions concerning the semantics of disjunctive databases and of logic pro gramming systems depend on the xed points of various multivalued mappings and operators determined by the database or program We discuss known versions for mul tivalued mappings of the Knaster Tarski theorem and of the Banach contraction map ping theorem and formulate a version of the classical xed point theorem s...

Sibylla Priess-Crampe and Paulo Ribenboim recently established a general xed-point theorem for multivalued mappings deened on generalized ultrametric spaces, and introduced it to the area of logic programming semantics. We discuss, in this context, the applications which have been made so far of this theorem and of its corollaries. In particular, we will relate these results to Scott-Ershov dom...

Sibylla Priess-Crampe and Paulo Ribenboim recently established a general xed-point theorem for multivalued mappings deened on generalized ultrametric spaces, and introduced it to the area of logic programming semantics. We discuss, in this context, the applications which have been made so far of this theorem and of its corollaries. In particular, we will relate these results to Scott-Ershov dom...

This paper presents a Banach space based approach towards a denotational semantics of a probabilistic constraint programming language. This language is based on the concurrent constraint programming paradigm, where randomness is introduced by means of a probabilis-tic choice construct. As a result, we obtain a declarative framework, in which randomised algorithms can be expressed and formalised...