From: Sam Yoffe sam.yoffe [snail] ed.ac.uk 16 April 2009 I was wondering if, in Predrag's book, he meant to use n! (as in n = defining dimension) in equation 6.28? If not, what is N? Tony Kennedy: It does look as though N ought to be n. I am copying this to Predrag so he can make a correction if necessary (now that it is too late to stop the presses!). (Tony to Predrag: Sam is trying to show by birdtracks that the square of a Pfaffian is a determinant).