He is the research director (emeritus) at the mathematical institute of Luminy. Jean-Yves Girard is an alumnus of the École normale supérieure de Saint-Cloud. He made a name for himself in the 1970s with his proof of strong normalization in a system of second-order logic called System F. This result gave a new proof of Takeuti"s conjecture, which was proven a few years earlier by William West. Tait, Moto-o Takahashi and Dag Prawitz.
Foreign this purpose, he introduced the notion of reducibility candidate ("candidat de réducibilité").
He is also credited with the invention of linear logic. The geometry of interaction.
Ludics. And the mustard watch.