Here is the problem:
show that if f:A B and G, H are substes of B, then
(G H) = (G) (H)
and
(G H) = (G) (H)
So I understand the main principle behind an inverse, such that if f(x) H, then x (H). I also understand the proof for inverse composite functions. But this is confusing. How do I prove this?? Thank you