In this paper we establish two alternative principles of the following type: If X and Y are convex subsets of two locally convex Hausdorff topological vector spaces and F, S : X Y are two set-valued mappings satisfying certain conditions, then either there exists x0 ∈ X such that F(x0) = ∅ or⋂x∈X S(x) = ∅. As first applications of the alternative principles we obtain two matching theorems of Ky...

We prove the following result. Let C be a convex compact subset in a topological vector space, and T : C → C a convex continuous mapping. (See Definition 1.1.) Then T has a fixed point. Moreover, continuous mappings that can be approximated by convex continuous mappings also have the fixed point property.

Let V and X be Hausdorr, locally convex, real, topological vector spaces with dimV > 1. We show that a map from an open, connected subset of V onto an open subset of X is homeomorphic and convexity-preserving if and only if is projective.

In this paper, we formalize the Menger probabilistic normed space as a category in which its objects are the Menger probabilistic normed spaces and its morphisms are fuzzy continuous operators. Then, we show that the category of probabilistic normed spaces is isomorphicly a subcategory of the category of topological vector spaces. So, we can easily apply the results of topological vector spaces...

1. N o t a t i o n a n d pre l iminary ideas . A sequence space is a vector subspace of the space co of all real (or complex) sequences. A sequence space E with a locally convex topology r is called a Kspace if the inclusion map E —* co is continuous, when co is endowed with the product topology (co = II^Li (R)*). A i£-space E with a Frechet (i.e., complete, metrizable and locally convex) topol...

in this paper, a new definition of fuzzy bounded sets and totallyfuzzy bounded sets is introduced and properties of such sets are studied. thena relation between totally fuzzy bounded sets and n-compactness is discussed.finally, a geometric characterization for fuzzy totally bounded sets in i- topologicalvector spaces is derived.

This article is dedicated to the study of quasinormable injective tensor products of locally convex spaces and quasinormable spaces of continuous linear operators. The stability of the quasinormability is obtained in the frame of the class of spaces which are quasinormable by operators; this class, introduced and studied here, contains many function spaces. The problems considered in the articl...

Salas and Tapia-García introduced the concept of an extended locally convex space in [13] which extends idea normed (introduced by Beer [2]). This article gives attractive formulation finest topology provides a systematic study resulting space. As application, we characterize coincidence topologies corresponding to uniform strong convergences on bornology for function C(X).