Existence of positive fixed points for semidifferentiable semicompact 1- set contractions (Q1206547)

Let \(X\) be a linear space and let \(N\), \(|\;|: x\to [0,+\infty)\). We shall say that \((X,N,|\;|)\) is a quasi-Banach space if any closed ball with respect to the norm \(N\) is a complete metric space with the metric induced by \(|\;|\). The author considers condensing mappings for subsets of quasi-Banach spaces. Some generalizations of Sadovski's fixed point theorem are obtained.