@VideCorSpoon,
Well, grander might not be the right word for it. Allow me to show what I'm referring to:
1) P?Q is a logical equivalence of ?(?P??Q), because

Definition:
The formula's A and B are logical equivalent if and only if "(a) = "(b)
Theorem:
The formula's A and B are logical equivalent if and only if the truth values of (A?B) is a tautology.
2) The formula (P?Q)?(Q?P) is a tautology, because
Definition:
The formula A is a tautology when "(a)=1
3)The formula (P??P) is a contradition, because

Definition:
A formula A is a contradiction if and only if "(a)=0
4) The formula P??P is a contingency, because

Definition:
A formula A is a contingency if and only if $(a)=0 and $(a)=1.
I was wondering if there are more that I know nothing about.