NProof | When a brilliant but unstable University of Chicago mathematician dies, his daughter Catherine must face her fear of a possible connection between genius and madness. The puzzle in David Auburn's 2001 Pulitzer winner is how the titular proof, a labor of love meant to disguise mental illness, can also be a mathematical breakthrough. Gregory Gerhard's staging creates sympathy for Catherine as she makes various choices--between staying in Chicago or moving to New York, for example. Leah Wagner's Valley-girl petulance isn't very Hyde Park, but she delivers the wrenching self-effacement behind Catherine's unsung brilliance. Brian Parry gives authority to the failing professor, Jason Daniels is salt-of-the-earth sincere as Catherine's geeky admirer, and Jacqueline Grandt sharply etches Catherine's rich but ordinary sister. --Lawrence Bommer a Through 12/10: Fri-Sat 8 PM, Sun 3 PM, Actors Workshop Theatre, 1044 W. Bryn Mawr, 773-728-7529, $20-$25, $10 industry through 12/3.