lean4-htt/tests/lean/run/968.lean
2022-01-22 09:42:59 -08:00

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theorem and_comm (a b : Prop) : (a ∧ b) = (b ∧ a) := sorry
theorem and_assoc (a b c : Prop) : ((a ∧ b) ∧ c) = (a ∧ (b ∧ c)):= sorry
theorem and_left_comm (a b c : Prop) : (a ∧ (b ∧ c)) = (b ∧ (a ∧ c)) := sorry
example (p q r : Prop) : (p ∧ q ∧ r)
= (r ∧ p ∧ q) :=
by simp only [and_comm, and_left_comm, and_assoc]
example (p q r : Prop) : ((let_fun x := p; x) ∧ (let_fun x := q; x) ∧ (let_fun x := r; x))
= ((let_fun x := r; x) ∧ (let_fun x := p; x) ∧ (let_fun x := q; x)) :=
by simp only [and_comm, and_left_comm, and_assoc]