Propositional logic De-morgans theorem question the theorem states that $(A\wedge B) = \neg (\neg A\vee \neg B)$, where $A$ and $B$ are propositional formulas.
Can't I turn $\neg (\neg A\vee \neg B)$ to $(\neg \neg A\vee \neg \neg B)$ then cancel the double negations so its $(A\vee B)$, because that seems to be allowed if $A$ and $B$ were propositions.

$$\neg(\neg A \vee \neg B) \iff \neg\neg A \wedge \neg\neg B \iff A \wedge B $$
