Anders Lindstedt

Anders Lindstedt was a Swedish mathematician, astronomer and actuarial scientist, born in a small village in the district of Sundborn in Dalarna on 27 June 1854 and died on 16 May 1939. He took his PhD at the University of Lund at the age of thirty two, lectured there in astronomy, and then spent about seven years on theoretical astronomy at the University of Dorpat, now Tartu, where his interest in the three-body problem influenced Henri Poincaré. His papers on celestial mechanics include a technique for uniformly approximating periodic solutions of ordinary differential equations when regular perturbation fails, later developed by Poincaré and known as the Lindstedt-Poincaré method. He returned to Sweden in 1886 as professor at the Royal Institute of Technology in Stockholm, serving as its rector from 1903 to 1909, and then turned to insurance mathematics, constructing a Swedish life table for annuities in 1912 and directing the actuarial work behind the 1913 National Pension Act.