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Almost strongly regular matrices and a core theorem for double sequences. (English) Zbl 1043.40002
Summary: The idea of almost convergence for double sequences was introduced by {\it F. Móricz} and {\it B. E. Rhoades} [Math. Proc. Camb. Philos. Soc. 104, 283--294 (1988; Zbl 0675.40004)] and they also characterized the four dimensional strong regular matrices. In this paper we define and characterize the almost strongly regular matrices for double sequences and apply these matrices to establish a core theorem.

40A05Convergence and divergence of series and sequences
Full Text: DOI
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