propositional logic – Converting to CNF – Distribution

I am still trying to get my head around what is valid CNF and how distribution works, I am not even sure if the examples I have tried to convert are correct for one, but I am also unsure of the rule for distribution and when I have looked at other posts here it seems so complicated and the actual rule does not seem to me to be obvious.

I think the correct process is:

  • Elimate Bi-Directionals
  • Eliminate Implications
  • Apply De Morgans Law
  • Apply Distributive Law

Clause One

A V B => C
-(A V B) V C -- Remove implication
(-A ^ -B) V C -- De Morgans Law
(-A V C) ^ (-B V C) -- Is this right? I am unsure of exactly how to distribute the or.

Clause Two

A ^ B => C
-(A ^ B) V C -- Eliminate Implication
(-A V -B) V C -- Is this now valid CNF or is there something more to do?

Clause Three

-A ^ -B => C
(A ^ B) V C -- Elimate Implication - Is this correct for a negated expression?
(A V C) ^ (B V C) -- Distribute OR - Is this correct?

I am not able to access the set of maths symbols for some reason so have used the notation in my course book.

I am currently taking a self taught course and have an exam in two weeks and I know there will conversion to CNF involved so I am trying to make sure I understand the steps now but I am still not entirely sure what is valid CNF.

The course material states it is a conjunction of disjunctions which I get, but then it seems to imply that: A V B V C V ..n is valid CNF?