Ákos Császár (born 26 February 1924, Budapest) is a Hungarian mathematician, specializing in general topology and real analysis. He discovered the Császár polyhedron, a nonconvex polyhedron without diagonals.[1] He introduced the notion of syntopogeneous spaces, a generalization of topological spaces.
Between 1952 and 1992 he was head of the Department of Analysis at the Eötvös Loránd University, Budapest. Corresponding member (1970), member (1979) of the Hungarian Academy of Sciences.[2] He has been general secretary (1966–1980), president (1980–1990), honorary president (since 1990) of the János Bolyai Mathematical Society. He received the Kossuth Prize (1963) and the Gold Medal of the Hungarian Academy of Sciences (2009).[3][4]