Based on the Pulitzer Prize-winning play by David Auburn, Proof follows a devoted daughter (Paltrow) who comes to terms with the death of her father (Hopkins) a brilliant mathematician whose genius was crippled by mental insanity -- and is forced to face her own long-harbored fears and emotions. <br/> <br/>She adjusts to his death with the help of one of her father's former mathematical students (Gyllenhaal) who searches through her father's notebooks in the hope of discovering a bit of his old brilliance. <br/> <br/>While coming to terms with the possibility that his genius, which she has inherited, may come at a painful price, her estranged sister (Davis) arrives to help settle their father's affairs.