On absolute double summability methods with high indices

Abstract

In a recent paper, [SARIGÖL, M. A.: Characterization of summability methods with high indices, Math. Slovaca 63 (2013), 1053–1058], the equivalence | C , 0 | _k ⟺ | R , p _n | _k , k ≥ 1 was characterized for infinite single series. In the present paper, this result is extended to doubly summability a different approach.