Module: Mathlib.Topology.Algebra.Valued.ValuedField

Goal state before:
pp: case neg
K : Type u_1
inst✝¹ : Field K
Γ₀ : Type u_2
inst✝ : LinearOrderedCommGroupWithZero Γ₀
hv : Valued K Γ₀
a b : (ofClass v).ValueGroup₀
x : K := ⋯.choose
hx_def : x = ⋯.choose
y : K := ⋯.choose
hy_def : y = ⋯.choose
xy : K := ⋯.choose
hxy_def : xy = ⋯.choose
hxy : v xy = embedding a * embedding b
hx : v x = embedding a
hy : v y = embedding b
hx0 : ¬x = 0
hy0 : ¬y = 0
⊢ ↑⟨Units.mk0 (v xy) ⋯, ⋯⟩ = ↑⟨Units.mk0 (v x) ⋯, ⋯⟩ * ↑⟨Units.mk0 (v y) ⋯, ⋯⟩

pp: case neg.hnc
K : Type u_1
inst✝¹ : Field K
Γ₀ : Type u_2
inst✝ : LinearOrderedCommGroupWithZero Γ₀
hv : Valued K Γ₀
a b : (ofClass v).ValueGroup₀
x : K := ⋯.choose
hx_def : x = ⋯.choose
y : K := ⋯.choose
hy_def : y = ⋯.choose
xy : K := ⋯.choose
hxy_def : xy = ⋯.choose
hxy : v xy = embedding a * embedding b
hx : v x = embedding a
hy : v y = embedding b
hx0 : ¬x = 0
hy0 : ¬y = 0
⊢ ¬extensionValuation ↑x = 0

pp: case neg.hnc
K : Type u_1
inst✝¹ : Field K
Γ₀ : Type u_2
inst✝ : LinearOrderedCommGroupWithZero Γ₀
hv : Valued K Γ₀
a b : (ofClass v).ValueGroup₀
x : K := ⋯.choose
hx_def : x = ⋯.choose
y : K := ⋯.choose
hy_def : y = ⋯.choose
xy : K := ⋯.choose
hxy_def : xy = ⋯.choose
hxy : v xy = embedding a * embedding b
hx : v x = embedding a
hy : v y = embedding b
hx0 : ¬x = 0
hy0 : ¬y = 0
⊢ ¬extensionValuation ↑y = 0

pp: case neg.hnc
K : Type u_1
inst✝¹ : Field K
Γ₀ : Type u_2
inst✝ : LinearOrderedCommGroupWithZero Γ₀
hv : Valued K Γ₀
a b : (ofClass v).ValueGroup₀
x : K := ⋯.choose
hx_def : x = ⋯.choose
y : K := ⋯.choose
hy_def : y = ⋯.choose
xy : K := ⋯.choose
hxy_def : xy = ⋯.choose
hxy : v xy = embedding a * embedding b
hx : v x = embedding a
hy : v y = embedding b
hx0 : ¬x = 0
hy0 : ¬y = 0
⊢ ¬extensionValuation ↑xy = 0

Tactic:
· simp only [← WithZero.coe_mul, MulMemClass.mk_mul_mk, WithZero.coe_inj, Subtype.mk.injEq]
          rw [← Units.mk0_mul]
          · ext
            simp [Units.val_mk0, hx, hy, hxy]
          · aesop

Goal state after:
case neg.hnc
K : Type u_1
inst✝¹ : Field K
Γ₀ : Type u_2
inst✝ : LinearOrderedCommGroupWithZero Γ₀
hv : Valued K Γ₀
a b : (ofClass v).ValueGroup₀
x : K := ⋯.choose
hx_def : x = ⋯.choose
y : K := ⋯.choose
hy_def : y = ⋯.choose
xy : K := ⋯.choose
hxy_def : xy = ⋯.choose
hxy : v xy = embedding a * embedding b
hx : v x = embedding a
hy : v y = embedding b
hx0 : ¬x = 0
hy0 : ¬y = 0
⊢ ¬extensionValuation ↑x = 0

case neg.hnc
K : Type u_1
inst✝¹ : Field K
Γ₀ : Type u_2
inst✝ : LinearOrderedCommGroupWithZero Γ₀
hv : Valued K Γ₀
a b : (ofClass v).ValueGroup₀
x : K := ⋯.choose
hx_def : x = ⋯.choose
y : K := ⋯.choose
hy_def : y = ⋯.choose
xy : K := ⋯.choose
hxy_def : xy = ⋯.choose
hxy : v xy = embedding a * embedding b
hx : v x = embedding a
hy : v y = embedding b
hx0 : ¬x = 0
hy0 : ¬y = 0
⊢ ¬extensionValuation ↑y = 0

case neg.hnc
K : Type u_1
inst✝¹ : Field K
Γ₀ : Type u_2
inst✝ : LinearOrderedCommGroupWithZero Γ₀
hv : Valued K Γ₀
a b : (ofClass v).ValueGroup₀
x : K := ⋯.choose
hx_def : x = ⋯.choose
y : K := ⋯.choose
hy_def : y = ⋯.choose
xy : K := ⋯.choose
hxy_def : xy = ⋯.choose
hxy : v xy = embedding a * embedding b
hx : v x = embedding a
hy : v y = embedding b
hx0 : ¬x = 0
hy0 : ¬y = 0
⊢ ¬extensionValuation ↑xy = 0