Proving this is a wff (well-formed formula)
¬((P ∨ Q) ∧ ¬(¬Q ∨ R))
P, Q, and R are all wffs (atomic propositions are all wffs)
P ∨ Q is a wff.
¬(¬Q ∨ R)
0, 0 ⇒ 0
1, 0 ⇒ 1
0, 1 ⇒ 0
1, 1 ⇒ 0
Q ∧ ¬R
¬((P ∨ Q) ∧ (Q ∧ ¬R))
every WFF must have a unique parse tree.
I.e. P ∨ Q ∧ R is not a WFF does not have a unique parse tree