Recent content by J.T2015

Can someone explain the determinant of the derivative in the neighbourhood of a is also nonzero when derivative at a is the identity map? I found related sentence in wikipedia ''if the Jacobian determinant at p is positive, then F preserves orientation near p; if it is negative, F reverses...

Can u make further explanation for 'all functions with derivative equal to the identity, then we can also prove it for all functions with invertible derivative', how's that makes sense?