Measures of noncompactness in (N¯q∆) summable difference sequence spaces


Ishfaq Ahmad Malik, Tanweer Jalal




In this paper we first introduce ¯Nq∆ summable difference sequence spaces and prove some properties of these spaces. We then obtain the necessary and sufficient conditions for infinite matrices A to map these sequence spaces into the spaces c, c0, and l∞. Finally, the Hausdorff measure of noncompactness is then used to obtain the necessary and sufficient conditions for the compactness of the linear operators defined on these spaces.