I am learning CNF and I have a teacher who is doing something I truly don't understand. I want to ask him later on, yet I am struggling to finish my coursework so it can't wait until then.
So..
-A --> B
It needs to be -A v B. This one... this one is fine, I get it.
The thing starts when he goes further and says that it needs to be: -A, B... and, after that, A,B
And I am stunned. How does he get -A, B and derive A,B from that? And on Wikipedia, I can't read anything about changing -A v B to something else...
Can someone help me by confirming that I am right and that it should be -A v B... and only that?
I think I see what is going on ...
OK, we have that:
$A \rightarrow B \Leftrightarrow \neg A \lor B$ (you can use a truth-table to verify this)
But that means:
$\neg A \rightarrow B \Leftrightarrow$
$\neg \neg A \lor B \Leftrightarrow$
$A \lor B$
Is that maybe what your instructor is trying to do?