John Nash

Died: May 23, 2015.

John Forbes Nash, who has died with his wife in a car crash aged 86, was the mathematical genius whose struggle with schizophrenia was chronicled in the 2001 film A Beautiful Mind.

Known as brilliant and eccentric, Nash was associated with Princeton University for many years, most recently serving as a senior research mathematician. He won the Nobel Prize in economics in 1994 for his work in game theory, which offered insight into the dynamics of human rivalry. It is considered one of the most influential ideas of the 20th century.

In an autobiography written for The Nobel Foundation Web site, Nash said delusions caused him to resign as a faculty member at the Massachusetts Institute of Technology (MIT). He also spent several months in New Jersey hospitals on an involuntary basis.

However, Nash's schizophrenia diminished through the 1970s and 1980s as he said he gradually began to intellectually reject some of the delusional lines of thinking.

A Beautiful Mind won four Oscars, including best picture and best director, and generated interest in John Nash's life story. The film was based on an unauthorised biography by Sylvia Nasar, who wrote that Nash's contemporaries found him immensely strange and slightly cold, a bit superior, and somewhat secretive.

Much of his demeanour is likely to have stemmed from mental illness, which began emerging in 1959 when Alicia was pregnant with a son. The film, though, did not mention Nash's older son or the years that he and Alicia spent living together after divorcing. The couple split in 1963, then resumed living together several years later and finally remarried in 2001.

Born in Bluefield, West Virginia, to an electrical engineer and a housewife, Nash had read the classic Men of Mathematics by ET Bell by the time he was in high school. He planned to follow in his father's footsteps and studied for three years at the Carnegie Institute of Technology in Pittsburgh (now Carnegie Mellon University), but instead developed a passion for mathematics.

He then went to Princeton, where he worked on his equilibrium theory and, in 1950, received his doctorate with a dissertation on non-cooperative games. The thesis contained the definition and properties of what would later be called the Nash equilibrium.

Nash then taught at MIT for several years and held a research post at Brandeis University before eventually returning to Princeton.

Nash and Alicia Nash, 82, of Princeton Township, were killed in a taxi crash on Saturday. Russell Crowe, who portrayed Nash in A Beautiful Mind, tweeted that he was stunned. "An amazing partnership," he wrote. "Beautiful minds, beautiful hearts."

Just a few days ago, Nash had received a prize from the Norwegian Academy of Sciences and Letters in Oslo with New York University mathematician Louis Nirenberg, who said he had chatted with the couple for an hour at the airport in Newark before they had taken a cab. Nirenberg said Nash was a truly great mathematician and a kind of genius.

"We were all so happy together," Nirenberg said. "It seemed like a dream."

"John's remarkable achievements inspired generations of mathematicians, economists and scientists who were influenced by his brilliant, groundbreaking work in game theory," Princeton University President Christopher Eisgruber said in a statement.

"The story of his life with Alicia moved millions of readers and moviegoers who marveled at their courage in the face of daunting challenges," he added.