case pos
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
⊢ annIdealGenerator 𝕜 a = minpoly 𝕜 a

case neg
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : ¬annIdealGenerator 𝕜 a = 0
⊢ annIdealGenerator 𝕜 a = minpoly 𝕜 a
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
⊢ annIdealGenerator 𝕜 a = minpoly 𝕜 a
by_cases h : annIdealGenerator 𝕜 a = 0
case pos
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
⊢ ¬IsIntegral 𝕜 a
case pos
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
⊢ annIdealGenerator 𝕜 a = minpoly 𝕜 a
rw [h, minpoly.eq_zero]
case pos.intro.intro
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
p : 𝕜[X]
p_monic : Monic p
hp : ↑(aeval a) p = 0
⊢ False
case pos
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
⊢ ¬IsIntegral 𝕜 a
rintro ⟨p, p_monic, hp : aeval a p = 0⟩
case pos.intro.intro
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
p : 𝕜[X]
p_monic : Monic p
hp : ↑(aeval a) p = 0
⊢ p ∈ ⊥
case pos.intro.intro
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
p : 𝕜[X]
p_monic : Monic p
hp : ↑(aeval a) p = 0
⊢ False
refine' p_monic.ne_zero (Ideal.mem_bot.mp _)
no goals
case pos.intro.intro
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : annIdealGenerator 𝕜 a = 0
p : 𝕜[X]
p_monic : Monic p
hp : ↑(aeval a) p = 0
⊢ p ∈ ⊥
simpa only [annIdealGenerator_eq_zero_iff.mp h] using mem_annIdeal_iff_aeval_eq_zero.mpr hp
no goals
case neg
𝕜 : Type u_1
A : Type u_2
inst✝² : Field 𝕜
inst✝¹ : Ring A
inst✝ : Algebra 𝕜 A
a : A
h : ¬annIdealGenerator 𝕜 a = 0
⊢ annIdealGenerator 𝕜 a = minpoly 𝕜 a
exact minpoly.unique _ _ (monic_annIdealGenerator _ _ h) (annIdealGenerator_aeval_eq_zero _ _)
  fun q q_monic hq =>
    degree_annIdealGenerator_le_of_mem a q (mem_annIdeal_iff_aeval_eq_zero.mpr hq)
      q_monic.ne_zero