See more of Princeton University on Facebook ||||| "He is a mathematical genius." 
 
 So ends a recommendation letter written for the late John Forbes Nash, Jr., who was applying to attend Prince University's graduate college in 1948. The famed mathematician, whose life was the subject of Oscar-winning film A Beautiful Mind, is globally recognized for his research in game theory, as well as his struggle with schizophrenia. He won the Nobel Prize in Economic Sciences in 1994. 
 
 See also: A math question has been stumping thousands of British students 
 
 The letter, which is dated Feb. 11, 1948 was written by well-known mathematician Richard J. Duffin, who kept it short and to the point: 
 
 Princeton published the letter online Thursday. 
 
 John and his wife Alicia Nash died in a car accident in New Jersey late last month. ||||| Mathematician Richard J. Duffin kept his letter recommending John Nash for graduate school at Princeton University brief. 
 
 But the Feb. 11, 1948 letter includes a powerful line in support of Nash: "He is a mathematical genius." 
 
 Nash was accepted. 
 
 The man whose life was the subject of the movie "A Beautiful Mind" went on to win the Nobel Prize for economics in 1994. Nash was recently awarded the Abel Prize for mathematics. 
 
 Nash, and his wife, Alicia Nash, died last month in a crash on the New Jersey Turnpike after returning from Norway to receive the top mathematics award. 
 
 Princeton University posted the letter from Duffin, as well as other documents from Nash's academic record, online last week. 
 
 Erin O'Neill may be reached at eoneill@njadvancemedia.com. Follow her on Twitter @LedgerErin. Find NJ.com on Facebook. ||||| John Nash — the Princeton game theorist who shared the 1994 Nobel Prize in economics and was portrayed by Russell Crowe in A Beautiful Mind — died in a car crash on May 23, along with his wife, Alicia. In light of his passing, Princeton has digitized his academic file and released it to the public; you can see the full PDF here. 
 
 Probably the best document it contains is a recommendation letter by Richard Duffin, Nash's undergraduate advisor at the Carnegie Institute of Technology (now Carnegie Mellon), to Solomon Lefschetz, a math professor at Princeton, where Nash was applying to grad school: 
 
 The letter was successful. Nash went on to get his PhD at Princeton. His dissertation, "Non-cooperative games," introduced a concept that would become known as the "Nash equilibrium," a crucial concept in game theory. Khan Academy explains the idea, and how it relates to the famous prisoner's dilemma game, here: 
 
 Nash's dissertation has been cited about 7,189 times, according to Google Scholar, though that excludes many uses of the term "Nash equilibrium" that don't cite the actual paper. "If Nash got a dollar for every time someone wrote or said 'Nash equilibrium,'" Princeton economist Avinash Dixit once wrote, "he would be a rich man." 
 
 Nash submitted his thesis in May 1950, when he was 21 years old. It was a mere 27 pages long, which includes an acknowledgements section and a very short bibliography. The entire dissertation cites only two sources: game theory's founders John von Neumann and Oskar Morgenstern, and John Nash.
– Like a strong, simple letter of recommendation? Well it helps if the subject is a genius. Mathematician Richard Duffin wrote a letter to Princeton University for John Forbes Nash, Jr., who became an esteemed mathematician and the subject of the film A Beautiful Mind, Mashable reports. Dated Feb. 11, 1948, the letter reads: "This is to recommend John F. Nash, Jr. who has applied for entrance to the graduate college at Princeton. Mr. Nash is 19 years old and is graduating from Carnegie Tech in June. He is a mathematical genius. Yours Sincerely, Richard J. Duffin." The letter was successful, notes Vox, and Nash went on to win the Nobel Prize for Economics in 1994, the Star-Ledger reports. Nash and his wife died in a taxi crash last month, but weren't supposed to be in that taxi.