On Tornheim's double series

On absolute generalized Norlund summability of double orthogonal series

In the paper [Y. Okuyama, {it On the absolute generalized N"{o}rlund summability of orthogonal series},Tamkang J. Math. Vol. 33, No. 2, (2002), 161-165] the author has found some sufficient conditions under which an orthogonal seriesis summable $|N,p,q|$ almost everywhere. These conditions are expressed in terms of coefficients of the series. It is the purpose ofthis paper to extend this result...

On Summability of Double Series*

Double Sequences and Double Series

This research considers two traditional important questions, which are interesting, at least to most mathematicians. The first question arises in the theory of double sequences of complex numbers, which concerns the relationship, if any, between the following three limits of a double sequence s : N×N −→ C: 1. limn,m→∞ s(n, m), 2. limn→∞(limm→∞ s(n, m)), 3. limm→∞(limn→∞ s(n, m)). In particular,...

On Double Summability of Double Conjugate Fourier Series

H. K. Nigam and Kusum Sharma Department of Mathematics, Faculty of Engineering and Technology, Mody Institute of Technology and Science, Deemed University, Laxmangarh 332311, Sikar, Rajasthan, India Correspondence should be addressed to Kusum Sharma, [email protected] Received 20 January 2012; Accepted 1 March 2012 Academic Editor: Ram U. Verma Copyright q 2012 H. K. Nigam and K. Sha...

On Evaluations of Infinite Double Sums and Tornheim’s Double Series

We consider generalizations of a sum, which was recently analyzed by Pemantle and Schneider using the computer software Sigma, and later also by Panholzer and Prodinger. Our generalizations include Tornheim’s double series as a special case. We also consider alternating analogs of Tornheim’s series. For Tornheim’s double series and its alternating counterparts we provide short proofs for evalua...