Andrey Tychonoff

Andrey Nikolayevich Tikhonov, whose surname is also transliterated Tychonoff, lived from 1906 to 1993 and was a leading Soviet Russian mathematician and geophysicist. Born in Gzhatsk, he studied at Moscow State University and received his doctorate there in 1927 under the direction of Pavel Sergeevich Alexandrov, becoming a professor in 1933 and later a full member of the USSR Academy of Sciences. He is best known for his work in topology, including the metrization theorem he proved in 1926 and Tychonoff's theorem, which states that every product of arbitrarily many compact topological spaces is again compact; completely regular spaces are named Tychonoff spaces in his honour. He also contributed to functional analysis, mathematical physics and the theory of ill-posed problems, where Tikhonov regularization bears his name, and he helped invent the magnetotellurics method in geophysics. He founded the Faculty of Computational Mathematics and Cybernetics at Moscow State University and was its first dean from 1970 to 1990.