Research

Following the Finnish tradition of Ernst Lindelöf, Rolf Nevanlinna and Lars Ahlfors, Ollo Lehto has studied complex analysis, first the classical theory and since the late 1950s quasiconformal mappings. Their importance was shown by Oswald Teichmüller just before the Wold War II, and thanks to Ahlfors, they became popular in many places of the world in the fifties. The books "Quasikonforme Abbildungen" (1965) and its new edition "Quasiconformal mappings in the plane" (1973), written with K. I. Virtanen were among the first comprehensive monographs of the theory. Many of his students, now professors or retired professors, made quasiconformal mappings and related areas a stronghold of Finnish mathematics.