Frederick Justin Almgren Jr. (July 3, 1933 – February 5, 1997) was an American mathematician working in geometric measure theory.
He also developed the concept of varifold,[3] first defined by L. C. Young in (Young 1951),[4] and proposed them as generalized solutions to Plateau's problem in order to deal with the problem even when a concept of orientation is missing.
Almgren was a student of Herbert Federer, one of the founders of geometric measure theory, and was the advisor and husband (as his second wife) of Jean Taylor.
His daughter, Ann S. Almgren, is an applied mathematician who works on computational simulations in astrophysics.
His son, Robert F. Almgren, is an applied mathematician working on market microstructure and trade execution.