Lars Ahlfors

Early life and education Ahlfors was born in Helsinki, Finland. His mother, Sievä Helander, died at his birth. His father, Karl Axel Mauritz Ahlfors, was a professor of engineering at the Helsinki University of Technology. He completed his doctorate from the University of Helsinki in 1930. Academic career Ahlfors began his academic career at Åbo Akademi and was appointed associate professor of mathematics at the University of Helsinki in 1933. He was awarded the Wihuri International Prize in 1968 and the Wolf Prize in Mathematics in 1981, whose citation concluded that every function theorist active at the time was in some measure a student of Ahlfors. He served as the Honorary President of the International Congress of Mathematicians in 1986 at Berkeley, California, in celebration of his 50th year of the award of his Fields Medal. == Mathematical contributions ==

Throughout his career Ahlfors made decisive contributions to several areas of complex analysis. Among his earliest results was the proof of the Denjoy–Carleman–Ahlfors theorem, which states that the number of asymptotic values approached by an entire function of order ρ along curves in the complex plane going toward infinity is less than or equal to 2ρ. His book Complex Analysis (1953) is the classic text on the subject and is almost certainly referenced in any more recent text which makes heavy use of complex analysis. Ahlfors wrote several other significant books, including Riemann surfaces (1960) and Conformal invariants (1973). He made decisive contributions to meromorphic curves, value distribution theory, Riemann surfaces, conformal geometry, quasiconformal mappings and other areas during his career. In 1954 Ahlfors proved that the results and conjectures of Oswald Teichmüller — whose pioneering work on Riemann surfaces had been cut short when he disappeared on the German Eastern Front in 1943 — were correct. In doing so he defined the concept of Teichmüller space, which rapidly became an important field of research within function theory and later acquired significance in physics as well. His work made the theory of quasiconformal mappings a central area of complex analysis, and by the year 2000 this theory was assessed as perhaps the most important advance in function theory during the 20th century. == Personal life ==

In 1933, he married Erna Lehnert, an Austrian born in Vienna who with her parents had first settled in Sweden and then in Finland. The couple had three daughters. Ahlfors died of pneumonia at the Willowwood nursing home in Pittsfield, Massachusetts in 1996. ==See also==