I cannot come up with the proof that (p => q) is the same as (not p => not q).

If anyone can help - that would be great.

As I understand it: (p => q) is always true except when p is true and q is false.

If that definition is true, then (not p => not q) cannot possibly be the same.

http://jasoninclass.wordpress.com/fi.../picture-1.png

This cannot be. What am I missing?

Thanks a million for any constructive help.

Jason