Theorem: WeierstrassCurve.Jacobian.Point.toAffine_add
File: Mathlib/AlgebraicGeometry/EllipticCurve/Jacobian.lean

tactic: by_cases hPz : P z = 0
state_before: R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

tactic: rw [toAffine_of_Z_eq_zero hPz, zero_add]
state_before: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
⊢ toAffine W (W.add P Q) = toAffine W Q

tactic: by_cases hQz : Q z = 0
state_before: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
⊢ toAffine W (W.add P Q) = toAffine W Q
state_after: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
hQz : Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W Q

case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
hQz : ¬Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W Q

tactic: rw [add_of_Z_eq_zero hP hQ hPz hQz, toAffine_smul _ <| (isUnit_X_of_Z_eq_zero hP hPz).pow 2,
  toAffine_zero, toAffine_of_Z_eq_zero hQz]
state_before: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
hQz : Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W Q
state_after: no goals

tactic: rw [add_of_Z_eq_zero_left hP.left hPz hQz,
  toAffine_smul _ <| (isUnit_X_of_Z_eq_zero hP hPz).mul <| Ne.isUnit hQz]
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : P z = 0
hQz : ¬Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W Q
state_after: no goals

tactic: by_cases hQz : Q z = 0
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

tactic: rw [add_of_Z_eq_zero_right hQ.left hPz hQz,
  toAffine_smul _ ((isUnit_X_of_Z_eq_zero hQ hQz).mul <| Ne.isUnit hPz).neg,
  toAffine_of_Z_eq_zero hQz, add_zero]
state_before: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: no goals

tactic: by_cases hxy : P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : ¬(P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3)
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

tactic: by_cases hx : P x * Q z ^ 2 = Q x * P z ^ 2
state_before: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3
hx : P x * Q z ^ 2 = Q x * P z ^ 2
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3
hx : ¬P x * Q z ^ 2 = Q x * P z ^ 2
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

tactic: rw [add_of_Y_ne' hP.left hQ.left hPz hQz hx <| hxy hx,
  toAffine_smul _ <| isUnit_dblZ_of_Y_ne' hP.left hQ.left hPz hx <| hxy hx,
  toAffine_add_of_Z_ne_zero hP hQ hPz hQz hxy]
state_before: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3
hx : P x * Q z ^ 2 = Q x * P z ^ 2
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: no goals

tactic: rw [add_of_X_ne hP.left hQ.left hPz hQz hx, toAffine_smul _ <| isUnit_addZ_of_X_ne hx,
  toAffine_add_of_Z_ne_zero hP hQ hPz hQz hxy]
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3
hx : ¬P x * Q z ^ 2 = Q x * P z ^ 2
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: no goals

tactic: rw [_root_.not_imp, not_ne_iff] at hxy
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : ¬(P x * Q z ^ 2 = Q x * P z ^ 2 → P y * Q z ^ 3 ≠ W.negY Q * P z ^ 3)
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q

tactic: rw [toAffine_of_Z_ne_zero hP hPz, toAffine_of_Z_ne_zero hQ hQz, Affine.Point.add_of_Y_eq
    ((X_eq_iff hPz hQz).mp hxy.left) ((Y_eq_iff' hPz hQz).mp hxy.right)]
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
⊢ toAffine W (W.add P Q) = toAffine W P + toAffine W Q
state_after: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
⊢ toAffine W (W.add P Q) = 0

tactic: by_cases hy : P y * Q z ^ 3 = Q y * P z ^ 3
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
⊢ toAffine W (W.add P Q) = 0
state_after: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
hy : P y * Q z ^ 3 = Q y * P z ^ 3
⊢ toAffine W (W.add P Q) = 0

case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
hy : ¬P y * Q z ^ 3 = Q y * P z ^ 3
⊢ toAffine W (W.add P Q) = 0

tactic: rw [add_of_Y_eq hPz hQz hxy.left hy hxy.right,
  toAffine_smul _ <| isUnit_dblU_of_Y_eq hP hPz hQz hxy.left hy hxy.right, toAffine_zero]
state_before: case pos
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
hy : P y * Q z ^ 3 = Q y * P z ^ 3
⊢ toAffine W (W.add P Q) = 0
state_after: no goals

tactic: rw [add_of_Y_ne hP.left hQ.left hPz hQz hxy.left hy,
  toAffine_smul _ <| isUnit_addU_of_Y_ne hPz hQz hy, toAffine_zero]
state_before: case neg
R : Type u
inst✝¹ : CommRing R
W' : Jacobian R
F : Type v
inst✝ : Field F
W : Jacobian F
P Q : Fin 3 → F
hP : W.Nonsingular P
hQ : W.Nonsingular Q
hPz : ¬P z = 0
hQz : ¬Q z = 0
hxy : P x * Q z ^ 2 = Q x * P z ^ 2 ∧ P y * Q z ^ 3 = W.negY Q * P z ^ 3
hy : ¬P y * Q z ^ 3 = Q y * P z ^ 3
⊢ toAffine W (W.add P Q) = 0
state_after: no goals