Exercise logic.propositional.dnf.unicode

Description
Proposition to DNF (unicode support)

Derivation

Final term is not finished

¬(¬q ∨ p) ↔ (¬s ∨ (r ↔ s))

⇒ logic.propositional.defequiv

¬(¬q ∨ p) ↔ (¬s ∨ (r ∧ s) ∨ (¬r ∧ ¬s))