In the present paper we essentially deal with to determine the neccessary and sufficient conditions in order for a matrix A=(ank) to belong to the classes (Xp:bs), (Xp:fs), (X1:lp), (Xp:X1) and (lp:X1), respectively. Furthermore, we give the sufficient conditions on a matrix A=(ank) in the class (Xp:lp) for 1<p<∞ and prove a Steinhaus type theorem concerning the disjointness of the classes (Xp:fs)r and (bs:fs). Those sequence spaces are described, below.
The present paper is concerned with the neccessary and sufficient conditions in order for a matrix A=(ank) to belong to the classes (l∞:Xp), (bs:Xp) and (bυ:Xp) respectively, where 1≤p≤∞. Furthermore, we prove that A∈(bs:μ) if and olny if B∈(l∞:μ) and use this to characterise the class (bs:Xp); where A and B are dual matrices and μ is any given sequence space.