variable (P Q R: Prop)

example : (1 ≤ 2) = (1 <= 2) := rfl
example : (1 ≤ 2) = (LE.le 1 2) := rfl

example : (1 ≥ 2) = (1 >= 2) := rfl
example : (1 ≥ 2) = (GE.ge 1 2) := rfl

example : (1 ≠ 2) = (Ne 1 2) := rfl
example : (1 ≠ 2) = (Not (1 = 2)) := rfl
-- native.lean:11:23: error: expected token
--example : (1 ≠ 2) = (1 ~= 2) := rfl

example : (¬P) = (Not P) := rfl
example : (P ∧ Q) = (P /\ Q) := rfl
example : (P ∧ Q) = (And P Q) := rfl
example : (P ∨ Q) = (P \/ Q) := rfl
example : (P ∨ Q) = (Or P Q) := rfl
example : (P → Q) = (P -> Q) := rfl
example : (P ↔ Q) = (P <-> Q) := rfl
example : (P ↔ Q) = (Iff P Q) := rfl

example : (Nat × Nat) = (Prod Nat Nat) := rfl

example : (∀ (x : Nat), x = 1) = (forall (x : Nat), x = 1) := rfl
example : (∃ (x : Nat), x = 1) = (exists (x : Nat), x = 1) := rfl
-- TODO produce an example where {{ actually matters vs {
example : (forall {{x : Nat}}, x = 1) = (forall ⦃x : Nat⦄, x = 1) := rfl
def «hello-world» : Nat := 5

-- Functions.
def inc : Int -> Int := λ (i: Int) ↦ i + 1
def incAscii : Int -> Int := fun (i: Int) => i + 1
example : inc = incAscii := rfl
example : inc (1) = 2 := rfl
example : incAscii (1) = 2 := rfl

-- Unknown identifier
--#check ℕ
--#check ℤ

-- Bullet
theorem bullet1 (p q : Prop) (hp : p) (hq : q) : p ∧ q := by
  apply And.intro
  . exact hp
  . exact hq
theorem bullet2 (p q : Prop) (hp : p) (hq : q) : p ∧ q := by
  apply And.intro
  · exact hp
  ·  exact hq
example : bullet1 = bullet2 := by rfl