Rudolf Otto Sigismund Lipschitz was a German mathematician who made contributions to mathematical analysis and differential geometry, as well as number theory, algebras with involution and classical mechanics.

Johann Peter Gustav Lejeune Dirichlet was a German mathematician. In number theory, he proved special cases of Fermat's last theorem and created analytic number theory. In analysis, he advanced the theory of Fourier series and was one of the first to give the modern formal definition of a function. In mathematical physics, he studied potential theory, boundary-value problems, and heat diffusion, and hydrodynamics.