Theorem: NNRat.cast_divNat_of_ne_zero
File: Mathlib/Data/Rat/Cast/Defs.lean

Proof steps:
state_before: F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
⊢ ↑(divNat a b) = ↑a / ↑b
state_after: case mk.mk'
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
n : ℤ
d : ℕ
h : d ≠ 0
c : n.natAbs.Coprime d
hn : 0 ≤ { num := n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := n, den := d, den_nz := h, reduced := c }, hn⟩
⊢ ↑⟨{ num := n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
tactic: rcases e : divNat a b with ⟨⟨n, d, h, c⟩, hn⟩
state_before: case mk.mk'
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
n : ℤ
d : ℕ
h : d ≠ 0
c : n.natAbs.Coprime d
hn : 0 ≤ { num := n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := n, den := d, den_nz := h, reduced := c }, hn⟩
⊢ ↑⟨{ num := n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
state_after: case mk.mk'
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
n : ℤ
d : ℕ
h : d ≠ 0
c : n.natAbs.Coprime d
hn✝ : 0 ≤ { num := n, den := d, den_nz := h, reduced := c }
hn : 0 ≤ { num := n, den := d, den_nz := h, reduced := c }.num
e : divNat a b = ⟨{ num := n, den := d, den_nz := h, reduced := c }, hn✝⟩
⊢ ↑⟨{ num := n, den := d, den_nz := h, reduced := c }, hn✝⟩ = ↑a / ↑b
tactic: rw [← Rat.num_nonneg] at hn
state_before: case mk.mk'
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
n : ℤ
d : ℕ
h : d ≠ 0
c : n.natAbs.Coprime d
hn✝ : 0 ≤ { num := n, den := d, den_nz := h, reduced := c }
hn : 0 ≤ { num := n, den := d, den_nz := h, reduced := c }.num
e : divNat a b = ⟨{ num := n, den := d, den_nz := h, reduced := c }, hn✝⟩
⊢ ↑⟨{ num := n, den := d, den_nz := h, reduced := c }, hn✝⟩ = ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
tactic: lift n to ℕ using hn
state_before: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
hd : ↑d ≠ 0
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
tactic: have hd : (d : α) ≠ 0 := by
    refine fun hd ↦ hb ?_
    have : Rat.divInt a b = _ := congr_arg NNRat.cast e
    obtain ⟨k, rfl⟩ : d ∣ b := by simpa [Int.natCast_dvd_natCast, this] using Rat.den_dvd a b
    simp [*]
state_before: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
hd : ↑d ≠ 0
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
hd : ↑d ≠ 0
hb' : b ≠ 0
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
tactic: have hb' : b ≠ 0 := by rintro rfl; exact hb Nat.cast_zero
state_before: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
hd : ↑d ≠ 0
hb' : b ≠ 0
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
tactic: have hd' : d ≠ 0 := by rintro rfl; exact hd Nat.cast_zero
state_before: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
e : divNat a b = ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
tactic: simp_rw [Rat.mk'_eq_divInt, mk_divInt, divNat_inj hb' hd'] at e
state_before: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ ↑⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩ = ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ ↑(num ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩) /
      ↑(den ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩) =
    ↑a / ↑b
tactic: rw [cast_def]
state_before: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ ↑(num ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩) /
      ↑(den ⟨{ num := ↑n, den := d, den_nz := h, reduced := c }, hn⟩) =
    ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ ↑n / ↑d = ↑a / ↑b
tactic: dsimp
state_before: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ ↑n / ↑d = ↑a / ↑b
state_after: case mk.mk'.intro
F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ ↑n * ↑b = ↑a * ↑d

F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ Commute ↑d ↑b
tactic: rw [Commute.div_eq_div_iff _ hd hb]
state_before: F : Type u_1
ι : Type u_2
α : Type u_3
β : Type u_4
inst✝ : DivisionSemiring α
q r : ℚ≥0
a b : ℕ
hb : ↑b ≠ 0
d : ℕ
h : d ≠ 0
n : ℕ
c : (↑n).natAbs.Coprime d
hn : 0 ≤ { num := ↑n, den := d, den_nz := h, reduced := c }
hd : ↑d ≠ 0
hb' : b ≠ 0
hd' : d ≠ 0
e : a * d = n * b
⊢ Commute ↑d ↑b
state_after: no goals
tactic: exact b.commute_cast _