Ms. McKellar had toyed with the idea of going to graduate school. "She certainly had the capability and talent to do that," Professor Chayes said. But by then, she had decided to return to acting. The academic world, she said, was too isolating and lonely. Professor Chayes said he was not disappointed. "I think disappointed is too strong," he said. "I would have been even happier if she were doing what she is doing now coupled with a career in mathematics." Since graduating in 1998 with highest honors, Ms. McKellar has reappeared on television, in her recurring role on "The West Wing," and as a guest star on shows like "NYPD Blue" and "Navy: NCIS." Her voice has been heard in the cartoons "King of the Hill" and "Justice League." She has also written and directed a couple of short films. The other member of the math proof team did continue in math. Ms. Winn, now Dr. Winn, completed her Ph.D. in mathematics at the University of Chicago this year. At U.C.L.A, Dr. Winn had decided to major in math before even meeting Ms. McKellar. But she said she had not expected to continue in the field beyond her bachelor's degree. "Pretty much because of Lincoln and Danica, I did go on," Dr. Winn said. Ms. McKellar remains enthusiastic about math.