Exercise logic.propositional.dnf.unicode

Description
Proposition to DNF (unicode support)

Derivation

Final term is not finished

¬(q → ¬¬p) ↔ ((r ↔ s) ∨ ¬s)

⇒ logic.propositional.notnot

¬(q → p) ↔ ((r ↔ s) ∨ ¬s)