D. Borwein et Jm. Borwein, ON SOME TRIGONOMETRIC AND EXPONENTIAL LATTICE SUMS, Journal of mathematical analysis and applications, 188(1), 1994, pp. 209-218
Certain two-dimensional trigonometric lattice series, the ordinary con
vergence of which involves unresolved questions of a deep and delicate
number-theoretic nature, are shown to be summable by a special Abelia
n method and their Abelian sums are obtained. This is done by first ev
aluating an absolutely convergent exponential lattice series and then
analytically extending its sum. (C) 1994 Academic Press, Inc.