-- Mathlib/RingTheory/DedekindDomain/Factorization.lean
theorem count_mono {I J} (hI : I ≠ 0) (h : I ≤ J) : count K v J ≤ count K v I

Proof state:
case neg
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
this : ∃ I_1, ↑I_1 = J⁻¹ * I
⊢ count K v J ≤ count K v I

Tactic:
obtain ⟨J', hJ'⟩ := this

Result:
case neg.intro
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
J' : Ideal R
hJ' : ↑J' = J⁻¹ * I
⊢ count K v J ≤ count K v I

Proof state:
case neg
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
⊢ count K v J ≤ count K v I

Tactic:
have := FractionalIdeal.mul_le_mul_left h J⁻¹

Result:
case neg
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
this : J⁻¹ * I ≤ J⁻¹ * J
⊢ count K v J ≤ count K v I

Proof state:
case neg
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
this : J⁻¹ * I ≤ J⁻¹ * J
⊢ count K v J ≤ count K v I

Tactic:
rw [inv_mul_cancel₀ hJ, FractionalIdeal.le_one_iff_exists_coeIdeal] at this

Result:
case neg
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
this : ∃ I_1, ↑I_1 = J⁻¹ * I
⊢ count K v J ≤ count K v I

Proof state:
case neg.intro
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
J' : Ideal R
hJ' : ↑J' = J⁻¹ * I
⊢ ↑J' ≠ 0

Tactic:
exact hJ' ▸ mul_ne_zero (inv_ne_zero hJ) hI

Result:
no goals

Proof state:
case neg.intro
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
J' : Ideal R
hJ' : ↑J' = J⁻¹ * I
⊢ 0 ≤ count K v ↑J'

Tactic:
exact count_coe_nonneg K v J'

Result:
no goals

Proof state:
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
⊢ count K v J ≤ count K v I

Tactic:
by_cases hJ : J = 0

Result:
case pos
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : J = 0
⊢ count K v J ≤ count K v I

case neg
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
⊢ count K v J ≤ count K v I

Proof state:
case neg.intro
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
J' : Ideal R
hJ' : ↑J' = J⁻¹ * I
⊢ count K v J ≤ count K v I

Tactic:
rw [← mul_inv_cancel_left₀ hJ I, ← hJ', count_mul K v hJ, le_add_iff_nonneg_right]

Result:
case neg.intro
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
J' : Ideal R
hJ' : ↑J' = J⁻¹ * I
⊢ 0 ≤ count K v ↑J'

case neg.intro
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : ¬J = 0
J' : Ideal R
hJ' : ↑J' = J⁻¹ * I
⊢ ↑J' ≠ 0

Proof state:
case pos
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsDedekindDomain R
v : HeightOneSpectrum R
I J : FractionalIdeal R⁰ K
hI : I ≠ 0
h : I ≤ J
hJ : J = 0
⊢ count K v J ≤ count K v I

Tactic:
exact (hI (FractionalIdeal.le_zero_iff.mp (h.trans hJ.le))).elim

Result:
no goals