Nash, of Princeton University, along with a professor at the University of California-Berkeley and a professor in Bonn, Germany, studied applications of game theory to economics.

Nash "introduced the distinction between cooperative games, in which binding agreements can be made, and noncooperative games, where binding agreements are not feasible," a 1994 Nobel Prize press release says.

"Some of the early studies developed from the idea of win or lose games that you might play for entertainment," Nash said in an interview Saturday. "But there's a more general type of theory which I was particularly involved with, the theory that it's not zero sum, and all the players can be winning to some extent."

Nash said he talked to people at the conference about his use of Mathematica, a popular software program for technical computing, particularly different types of algebra.

"John Nash's research has a lot of mathematical modeling," Mirdamadi said.

The workshop was free, but registration was cut off on Friday when it hit 150, he said. People attended from several states and Canada.

The 2001 movie "A Beautiful Mind" told of Nash's struggle with schizophrenia.

The mental illness surfaced in 1959, Nash wrote in an autobiographical statement posted on the Nobel Prize's Web site. He was committed to hospitals for treatment.

"And it did happen that when I had been long enough hospitalized that I would finally renounce my delusional hypotheses and revert to thinking of myself as a human of more conventional circumstances and revert to mathematical research," he wrote. "In these interludes of, as it were, enforced rationality, I did succeed in doing some respectable mathematical research."

Nash said Saturday his delusional thinking lasted off and on for about 25 years; the ending time "is not so precise."

"My problem now is age," said Nash, a Bluefield, W.Va., native who will turn 80 next month. "Some people really get Alzheimer's disease and it's variable.

"That's the thing. I'm able to do some good work, I think, but I probably don't have too much time. It's not like starting out on a long 50-year career, when it's a different story."