The "Bormat's Last Theorem" that is solved in the movie is clearly a reference to Fermat's Last Theorem. Like Bormat's theorem in the movie, Fermat's theorem was widely considered to be (one of) the most difficult problems of the last 300 years. It was solved fairly recently (in 1995 by Andrew Wiles). It was solved using elliptic curves, and the proof was first demonstrated at Cambridge. Like the proof of Bormat's theorem in the movie, the proving of Fermat's was a very big deal in the world of number theory.