‎"LOBATSCHEVSKY (LOBACHEVSKY, LOBACHEVSKII, LOBACEVSKIJ, LOBATSCHEWSKIJ), (NIKOLAI IVANOVITSCH).‎
‎Ueber die Convergenz der uendlichen Reihen (i.e. English: ""On the Convergence of Infinite Series"").‎

‎(Kazan, Universitäts-Buchdruckerei, 1841). 4to. In a contemporary modest half calf over marbled paper boards. Published in a supplement to ""Meteorologische Beobachtungen aus dem Lehrbezirk der Kaiserlich. Russischen Universitaet Kasan"". Heft 1, 1835–1836. 1841. Small stamp to upper outer corner of front free end-paper. A few leaves brownspotted. Book block split between pp. 4 and 5, otherwise a fine copy. 48 pp. ‎

Reference : 60236

‎Exceedingly rare first appearance of this work by Lobachevsky in which he returns to convergence of infinite series, on the foundations of calculus and real analysis, which he previous had dealt with in his 1834-textbook Algerbra and his 1834-paper ‘Ob ischezanii trigonometricheskikh strok’. Here, he expands and further develops the modern definition of the idea of a function in the works of Dirichlet, Poisson, and himself, adding and supplying more proofs. Primarily famous for his non-Euclidean geometry, Lobachevsky published a few papers on such nongeometrical subjects as algebra and the theoretical aspects of infinite series. The chief thrust of his scientific endeavor was, however, geometrical, and his later work was devoted exclusively to his new non-Euclidean geometry, the present work being one of his last on algebra and infinite series.‎