Numerical Functional Analysis and Optimization, vol.38, no.8, pp.1069-1076, 2017 (SCI-Expanded, Scopus)
In this paper, we prove that if a double series converges to α, then the power series Σi, jai, jxiyj converges for all x,y∈(0,1) and its sum is α, as x,y∈(1−, 1−). But the converse of this is not true, in general. Our main goal is to show that the converse of the idea, above, is true under which condition/conditions.