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)))