Stockholm, G. Mittag-Leffler, 1887. Folio (29.5 x 23.0 m). Six pp. [numbered 19-24]. Original printed wrappers.

First introduction of the Lerch zeta function, by the Czech mathematician Matthias Lerch (1860-1922). "In 1900, he was awarded the Grand Prize of the French Academy of Sciences for his number-theoretic work. The Lerch zeta function is named after him as is the Appell-Lerch sum. ... In mathematics, the Lerch zeta function, sometimes called the Hurwitz-Lerch zeta-function, is a special function that generalizes the Hurwitz zeta function and the polylogarithm" (Wikipedia). Offprint from Acta Mathematica, edited by G. Mittag-Leffler. Inscribed by the author in the top margin of the title page "À monsieur François Deruyts", i.e., the Belgian mathematician François Henri Gustave Deruyts (1864-1902) who died on the day that he was appointed as professor at the University of Liège. Uncut. Weak horizontal fold, therefore slight wear to edges, a bit more so to the thin wrappers. A very good copy with an interesting, meaningful dedication.