N Is a Number: A Portrait of Paul Erd?s is a 1993 documentary directed by George Paul Csicsery about the life of mathematician Paul Erd?s. 　　Erd?s himself appears in the film. As of 2007, using the official cast list in the credits, it gives Erd?s a Bacon number (and thus Erd?s-Bacon number) of 4. However, Sir Alec Guinness, identified by name by the narrator, appears in the film... (展開全部)