On real valued ω-continuous functions

The aim of this paper is to introduce and study upper and lower !-continuous functions. Some characterizations and several proper- ties concerning upper (resp. lower) !-continuous functions are obtained

Weakly (I, J)-continuous multifunctions and contra (I, J)-continuous multifunctions

The purpose of the present paper is to introduce, study and characterize upper and lower weakly (I, J)-continuous multifunctions and contra (I, J)-continuous multifunctions. Also, we investigate its relation with another class of continuous multifunctions. AMS Subject Classification: 54C10, 54C08, 54C05, 54C6

Θ-modifications on weak spaces

In this article, we want to study and investigate if it is possible to use the notions of weak structures to develop a new theory of - modi cations in weak spaces and study their properties, nally we study some forms of weak continuity using this modi cations

On property (Saw) and others spectral properties type Weyl-Browder theorems

An operator T acting on a Banach space X satisfies the property (aw) if σ(T) \ σw(T) = Ea(T), where σw(T) is the Weyl spectrum of T and Eo a(T) is the set of all eigenvalues of T of finite multiplicity that are isolated in the approximate point spectrum of T. In this paper we introduce and study two new spectral properties, namely (Saw) and (Sab), in connection with Weyl-Browder type theorems. Among other results, we prove that T satisfies property (Saw) if and only if T satisfies property (aw) and σSBF-+(T) = σw(T), where σSBF-+ (T) is the upper semi B-Weyl spectrum of T

Fuerte variación de los teoremas de tipo weyl y browder para sumas directas y restricciones.

In this paper, we study the stability under direct sums and restrictions of some strong variations of Weyl and Browder type theorems recently introduced in Rashid and Prasad (Asia-Eur J Math 8:14, 2015. https://doi.org/10.1142/S1793557115500126), Sanabria et al. (Rev Colomb Mat 51(2):153–171, 2017a, Acta Math Univ Comen (NS) 86(2):345–356, 2017b, Open Math 16(1):289–297, 2018).En este documento, estudiamos la estabilidad bajo sumas y restricciones directas de algunas variaciones importantes de los teoremas de tipo Weyl y Browder recientemente introducidos en Rashid y Prasad (Asia-Eur J Math 8:14, 2015. https://doi.org/10.1142 / S1793557115500126), Sanabria et al. (Rev Colomb Mat 51 (2): 153–171, 2017a, Acta Math Univ Comen (NS) 86 (2): 345–356, 2017b, Open Math 16 (1): 289–297, 2018)