Function is a change of variables?

[brunob]

Hi there!

The question is: if I have to prove that a function is a change of variable it is sufficient to prove that the function is a diffeomorphism? i.e. prove that the function is bijective, differentiable, and its inverse is differentiable?

Thanks!

 

[HallsofIvy]

What, exactly, is your definition of "change of variables"? How does it differ from a general function?