Appears in collection : Day in Honor of Yvonne Choquet-Bruhat’s 100 th Birthday

Yvonne Choquet-Bruhat has made fundamental contributions to both the mathematical and the physical understanding of Einstein's theory of gravitation. I will briefly summarize some of her achievements including: 1. The first proof of the existence of general (non analytic) solutions of Einstein's theory, including the first rigorous proof that they involve propagation phenomena at the velocity of light, i.e. gravitational waves; 2. Studies of relativistic fluids and of relativistic magneto-hydrodynamics; 3. A study of the exceptional properties of strong high-frequency gravitational waves;
4. Positivity of mass in a neighborhood of Minkowski space; 5. Causality of supergravity and study of Gauss-Bonnet gravity; 6. Existence proofs for classes of cosmological spacetimes; and 6. New formulations of Einstein's equations that proved crucial to the possibility of numerically simulating the motion and gravitational radiation of coalescing binary black holes.