17 lines
365 B
Text
17 lines
365 B
Text
theorem ex1 : a * 2 = 2 * a := by
|
|
have h : ∀ (a b : Nat), a * b = a * b := by
|
|
intros; rfl
|
|
conv at h =>
|
|
intro a b; lhs; rw [Nat.mul_comm]
|
|
exact h 2 a
|
|
|
|
#print ex1
|
|
|
|
theorem ex2 : a * 2 = 2 * a := by
|
|
have h : (fun x y => x * y) = Nat.mul := by
|
|
rfl
|
|
conv at h =>
|
|
lhs; intro x y; rw [Nat.mul_comm]
|
|
exact congrFun (congrFun h 2) a
|
|
|
|
#print ex2
|