congratulations to fan chung, distinguished professor emerita of mathematics and paul erdos professor in combinatorics, on her election to the national academy of sciences (nas).  professor chung graham joins a body of 2,617 active scientists who were elected by their peers to membership in the nas for outstanding contributions to research. the nas, established by an act of congress signed by president abraham lincoln in 1863, is committed to furthering science in america, and its members are active contributors to the international scientific community