Lappo-Danilevskii, Ivan

Born Oct. 16 (28), 1896, in St. Petersburg; died Mar. 15, 1931, in Giessen, Germany. Soviet mathematician. Corresponding member of the Academy of Sciences of the USSR (1931). Son of A. S. Lappo-Danilevskii.

I. A. Lappo-Danilevskii graduated from Leningrad University in 1925 and worked at a number of higher educational institutions in Leningrad. He constructed the theory of matrix functions and applied it in the solution of basic problems in the theory of linear differential equations, which made it possible for him to obtain a number of fundamental results.