Theorems
⊢ ∀P. (∃!x. P x) ⇔ ∃x. P x ∧ ∀y. P y ⇒ y = x
⊢ ∀P. P (if a then b else c) ⇔ (¬a ∨ P b) ∧ (a ∨ P c)
⊢ ∀P. P (if a then b else c) ⇔ a ∧ P b ∨ ¬a ∧ P c
⊢ a ∨ b ∧ c ⇔ (a ∨ b) ∧ (a ∨ c)
⊢ a ∧ b ∨ c ⇔ (a ∨ c) ∧ (b ∨ c)
⊢ a ∧ (b ∨ c) ⇔ a ∧ b ∨ a ∧ c
⊢ (a ∨ b) ∧ c ⇔ a ∧ c ∨ b ∧ c
⊢ f = (λx. t x) ⇔ ∀x. f x = t x
⊢ z = $@ P ⇒ ($? P ⇔ P z)
⊢ ¬(if p then q else q') ⇔ (p ∨ ¬q') ∧ (¬p ∨ ¬q)
⊢ ¬(if p then q else q') ⇔ p ∧ ¬q ∨ ¬p ∧ ¬q'
⊢ (p ⇎ q) ⇔ (p ∨ q) ∧ (¬p ∨ ¬q)
⊢ (p ⇎ q) ⇔ p ∧ ¬q ∨ ¬p ∧ q
⊢ (if p then q else q') ⇔ (p ∨ q') ∧ (¬p ∨ q)
⊢ (if p then q else q') ⇔ p ∧ q ∨ ¬p ∧ q'
⊢ (p ⇔ q) ⇔ (p ∨ ¬q) ∧ (¬p ∨ q)
⊢ (p ⇔ q) ⇔ p ∧ q ∨ ¬p ∧ ¬q
⊢ (a ∨ b) ∧ c ⇔ a ∧ c ∨ b ∧ c