Augustin Banyaga (born March 31, 1947) is a Rwandan-born American mathematician whose research fields include symplectic topology and contact geometry. He is currently a Professor of Mathematics at Pennsylvania State University.
Banyaga earned his Ph.D. degree in 1976 at the University of Geneva under the supervision of André Haefliger. He was a member of the Institute for Advanced Study in Princeton, New Jersey (1977–1978), Benjamin Peirce Assistant Professor at Harvard University(1978–1982), and Assistant Professor at Boston University (1982–1984), before joining the faculty at Pennsylvania State University in 1984 as Associate Professor. He was promoted to Full Professor in 1992.
He has made significant contributions in symplectic topology, especially on the structure of groups of diffeomorphisms preserving a symplectic form (symplectomorphisms). One of his best-known results states that the group of Hamiltonian diffeomorphisms of a compact, connected, symplectic manifold is a simple group; in particular, it does not admit any non-trivial homomorphism to the real line.
Banyaga is an editor of Afrika Matematica, the journal of the African Mathematical Union, and an editor of the
African Journal of Mathematics. He has supervised the theses of 7 Ph.D. students.