The maths in this movie is difficult and obscure. Try understanding the formula which is written here - or for that matter getting someone who knows mathematics to explain it to you!

It is easier to look for mistakes in the movie.

Here is one.

When John Nash, played by Russell Crowe, is teaching from the board at M.I.T. there is a sequence where he meets his future wife in the classroom. She is a student. Play the whole scene and look for the mistake in the formula written on the board.

It changes!!

The movie is a good one about a mathematician and possibly explains why mathematics teachers often see other people in their classrooms......

{ F : R3 \ X ? ?R3 so D X F=0 }

{ F : R3 \ X ? ?R so D X F=0 }