A normed vector space is a real or complex vector space in which a norm has been defined. Formally, one says that a normed vector space is a pair (V, ∥ · ∥) where V is a vector space over K and ∥ · ∥ is a norm in V , but then one usually uses the usual abuse of language and refers to V as being the normed space. Sometimes (frequently?) one has to consider more than one norm at the same time; th...

In terms of the normal cone and the coderivative, we provide some necessary and/or sufficient conditions of metric subregularity for (not necessarily closed) convex multifunctions in normed spaces. As applications, we present some error bound results for (not necessarily lower semicontinuous) convex functions on normed spaces. These results improve and extend some existing error bound results. ...

As a counterpart to best approximation, the concept of best coapproximation was introduced in normed linear spaces by C. Franchetti and M. Furi in 1972. Subsequently, this study was taken up by many researchers. In this paper, we discuss some results on the existence and uniqueness of best approximation and best coapproximation when the underlying spaces are metric linear spaces. A new kind of ...

in this paper, we use the de nition of fuzzy normed spaces givenby bag and samanta and the behaviors of solutions of the additive functionalequation are described. the hyers-ulam stability problem of this equationis discussed and theorems concerning the hyers-ulam-rassias stability of theequation are proved on fuzzy normed linear space.

In this paper, we define (λ, μ)statistical convergence and (λ, μ)-statistical Cauchy double sequences on intuitionistic fuzzy normed spaces (IFNS in short), where λ = (λn) and μ = (μm) be two non-decreasing sequences of positive real numbers such that each tending to ∞ and λn+1 ≤ λn +1, λ1 = 1; μm+1 ≤ μm + 1, μ1 = 1. We display example that shows our method of convergence is more general for do...

In this article we introduce the notions of I-limit superior and I-limit inferior for sequences in intuitionistic fuzzy normed linear spaces and prove intuitionistic fuzzy analogue of some results of I-limit superior and I-limit inferior for real sequences. The concept of I-limit points and I-cluster points in intuitionistic fuzzy normed linear spaces are introduced and some of their properties...

In this paper level-cut measures of noncompactness are introduced in standard fuzzy normed spaces and condensing operators are studied. Using the extensions of nonlinear compact operators, topological degree theory with respect to condensing operators is given in standard fuzzy normed spaces. As an application of degree theory, a fixed point theorem for condensing operators is presented. © 2009...

Given ann-normed space withn≥ 2, we offer a simple way to derive an (n−1)norm from the n-norm and realize that any n-normed space is an (n−1)-normed space. We also show that, in certain cases, the (n−1)-norm can be derived from the n-norm in such a way that the convergence and completeness in the n-norm is equivalent to those in the derived (n− 1)-norm. Using this fact, we prove a fixed point t...

The notion of a bead metric space is defined as a nice generalization of the uniformly convex normed space such as $CAT(0)$ space, where the curvature is bounded from above by zero. In fact, the bead spaces themselves can be considered in particular as natural extensions of convex sets in uniformly convex spaces and normed bead spaces are identical with uniformly convex spaces. In this paper, w...