1 We thank the anonymous referees and Professor F.Giannessi for helpful comments and suggestions which lead to improvement of the paper. Abstract. Quasi-P-maps and P(; ;)-maps deened in this paper are two large classes of nonlinear mappings which are broad enough to include P-maps as special cases. It is of interest that the class of quasi-P-maps also encompasses quasimono-tone maps (in particu...

In this paper, we consider more general forms of generalized vector quasi-equilibrium problems for multivalued maps which include many known vector quasi-equilibrium problems and generalized vector quasi-variational inequality problems as special cases. We establish some existence results for solutions of these problems under pseudomonotonicity and u-hemicontinuity/ -hemicontinuity assumptions.

The aim of this paper is to characterize in terms of classical (quasi)convexity of extended real-valued functions the set-valued maps which are K-(quasi)convex with respect to a convex cone K. In particular, we recover some known characterizations of K-(quasi)convex vector-valued functions, given by means of the polar cone of K.

The concept of pairwise S-closedness in bitopological spaces has been introduced and some properties of such spaces have been studied in this paper. EY WORDS AND PHRASES. Pairwise semi-open, Pairwise almost compact, Pairwise S-closed, Pairwise regularly open and regularly closed, Pairwise extremal disconnectedness, Pairwise semi-continuous and irresolute functions. 1980 AMS MATHEMATICS SUBJECT ...

In this paper, we give a new fixed point theorem forWeakly quasi-contraction maps in metric spaces. Our results extend and improve some fixed point and theorems in literature.