Abstract
Let $A$ and $B$ be two summability methods. We shall use the notation $\lambda \in(A, B)$ to denote the set of all sequences $\lambda$ such that $\sum\nolimits a_{n}\lambda_{n}$ is summable $B$, whenever $\sum\nolimits a_{n}$ is summable $A$. In the present paper we characterize the sets $\lambda \in (|\overline{N}, p_{n}|, |T|_{k})$ and $\lambda \in (|\overline{N}, p_{n}|_{k}, |T|)$, where $T$ is a lower triangular matrix with positive entries and row sums $1$. As special cases we obtain summability factor theorems and inclusion theorems for pairs of weighted mean matrices.
Citation
B. E. Rhoades. Ekrem Savas. "A CHARACTERIZATION OF ABSOLUTE SUMMABILITY FACTORS." Taiwanese J. Math. 8 (3) 453 - 465, 2004. https://doi.org/10.11650/twjm/1500407665
Information