MATHEMATICAL INEQUALITIES & APPLICATIONS, cilt.10, sa.1, ss.125-149, 2007 (SCI-Expanded)
We obtain sufficient conditions for the series Sigma Sigma a(mn), which is absolutely summable of order k by a double triangular matrix method A, to be such that Sigma Sigma a(mn)lambda(mn) is absolutely surnmable of order k by a double triangular matrix B. As corollaries we obtain a number of inclusion theorems.