Modification de la troisième demonstration donnée par Gauss de la loi de reprocité de legendre.

[Coimbra, Universidade de Coimbra, 1886]. 8vo (21.9 x 14.3 cm). 10 pp., contemporary (probably original) blind blue wrappers. = Important paper by the Czech mathematician Matyas Lerch (1860-1922), one of the country's greatest mathematicians and the first professor of mathematics at the Masaryk University in Brno. This being an offprint from the Jornal de Sciencias Mathematicas e Astronomicas. “Matyas Lerch was a remarkable Czech mathematician who published about 250 papers, some fifty of which were devoted to number theory. His favourite topics in number theory included binary quadratic forms, quadratic residues, Gauss sums and Fermat quotients. Also, the Lerch zeta-function is a well-known generalization of Riemann's zeta-function.” (M. Jutila). "Lerch won the Grand Prize of the Paris Academy in 1900 with a work on number theory, a great honour for any mathematician and an even greater achievement for a mathematician from outside France. He is also well-known, however, for his work in analysis. In that topic he studied infinite series, and the gamma function as well as other special functions. He also studied elliptic functions and integral equations" (O'Connor and Robertson). See also K. Lepka (Masaryk University, Faculty of Science, Brno, 1995), "Matyás Lerch's work on number theory". A fine, clean copy.