Albert Charles Schaeffer (13 August 1907, Belvidere, Illinois – 2 February 1957) was an American mathematician who worked on complex analysis.
Their goal was to give a proof for the fourth coefficient, but their approach would have required the numerical integration of about one million differential equations.
A little later, Paul Garabedian and Max Schiffer, then at Stanford, improved the Schaeffer–Spencer method and greatly reduced the number of necessary integrations.
In 1948, Schaeffer shared the Bôcher Memorial Prize with Spencer for their joint work on schlicht functions.
[2] In 1941, Schaeffer and R. J. Duffin put forward[3] a conjecture in metric diophantine approximation which was resolved in 2020 by James Maynard and Dimitris Koukoulopoulos.