DeMorgan's Law

[Michael Chui]

I've noticed that DeMorgan's Law is very useful when dealing with many situations that come up in the class and they haven't brought it up. So I'm just going to post it for reference:

~P OR ~Q <=> ~(P AND Q)

~P AND ~Q <=> ~(P OR Q)

http://en.wikipedia.org/wiki/De_Morgan's_laws

[Raf]

There is also another equivalence that I found very useful to solve quizzes:

(P => Q)  <=> (~P v Q)

Bye

Raf