premise: Matthew Benjamin Kleban is an American theoretical physicist who works on string theory and theoretical cosmology. He is an associate professor at New York University, a member of the Center for Cosmology and Particle Physics, and a former member at the Institute for Advanced Study. His contributions to physics include:
hypothesis: Matthew Benjamin Kleban is a member of the Institute for Advanced Study.
reason: The context paragraph states that he is a former member, not a current one.