Abstract
In this paper we investigate linear operators between arbitrary BK spaces X and spaces Y of sequences that are \({\text{(}}\bar N,q)\) summable or bounded. We give necessary and sufficient conditions for infinite matrices A to map X into Y. Further, the Hausdorff measure of noncompactness is applied to give necessary and sufficient conditions for A to be a compact operator.
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R. R. Akhmerov, M. I. Kamenskii, A. S. Potapov, A. E. Rodkina and B. N. Sadovskii: Measures of noncompactness and condensing operators. Oper. Theory Adv. Appl. 55 (1992). Birkhäuser Verlag, Basel.
A.M. Aljarrah and E. Malkowsky: BK spaces, bases and linear operators. Suppl. Rend. Circ. Mat. Palermo (2) 52 (1998), 177–191.
J. Banás and K. Goebl: Measures of noncompactness in Banach spaces. Lecture Notes in Pure and Appl. Math. 60 (1980). Marcel Dekker, New York and Basel.
G. H. Hardy: Divergent Series. Oxford University Press, 1973.
E. Malkowsky: Linear operators in certain BK spaces. Bolyai Soc. Math. Stud. 5 (1996), 259–273.
E. Malkowsky and S.D. Parashar: Matrix transformations in spaces of bounded and convergent difference sequences of order m. Analy sis 17 (1997), 87–97.
E. Malkowsky and V. Rako?ević: The measure of noncompactness of linear operators between certain sequence spaces. Acta Sci. Math. (Szeged) 64 (1998), 151–170.
E. Malkowsky and V. Rako?ević: The measure of noncompactness of linear operators between spaces of m th-order difference sequences. Studia Sci. Math. Hungar. 35 (1999), 381–395.
V. Rako?ević: Funkcionalna analiza. Nau?na knjiga. Beograd, 1994.
A. Wilansky: Summabilityt hrough functional analysis. North-Holland Math. Stud. 85 (1984).
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Malkowsky, E., Rakocevic, V. Measure of Noncompactness of Linear Operators between Spaces of Sequences That Are (N,q) Summable or Bounded. Czechoslovak Mathematical Journal 51, 505–522 (2001). https://doi.org/10.1023/A:1013727821173
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DOI: https://doi.org/10.1023/A:1013727821173