Proof is a play by American playwright David Auburn. After a development process at George Street Playhouse, the play premiered in 2000 Off Broadway, then transferred to Broadway at the Walter Kerr Theatre a few months later. It was directed by Daniel J. Sullivan and starred Mary-Louise Parker, Larry Bryggman, Ben Shenkman, and Johanna Day.
Proof tells the story of Catherine, whose father, a genius math professor at the University of Chicago, has recently died, after a struggle with mental illness. The play focuses on the events after his death; his former graduate student Hal discovers an extremely innovative new proof in his office. Catherine tries to prove that the proof is her work, even when Hal, and her intrusive sister, do not believe her.
The play was critically acclaimed, winning the Pulitzer Prize as well as a slew of other awards, including the Tony Award for Best Play in 2001. Awards also went to Mary-Louise Parker for her performance as Catherine, and Daniel Sullivan for his direction. In 2002, Gwyneth Paltrow starred in a West End production under John Madden's direction.