-- Mathlib/FieldTheory/IsAlgClosed/Classification.lean
theorem ringEquiv_of_Cardinal_eq_of_charP (p : ℕ) [Fact p.Prime] [CharP K p] [CharP L p]
    (hK : ℵ₀ < #K) (hKL : Nonempty (K ≃ L)) : Nonempty (K ≃+* L)

Proof state:
case intro.intro
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
⊢ Nonempty (K ≃+* L)

Tactic:
have hL : ℵ₀ < #L := by
  rwa [← aleph0_lt_lift.{v, u}, ← lift_mk_eq'.2 hKL, aleph0_lt_lift]

Result:
case intro.intro
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
hL : ℵ₀ < #L
⊢ Nonempty (K ≃+* L)

Proof state:
case intro.intro
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝¹ : Algebra (ZMod p) K := ZMod.algebra K p
this✝ : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
hL : ℵ₀ < #L
this : Cardinal.lift.{v, u} #↑s = Cardinal.lift.{u, v} #↑t
⊢ Nonempty (K ≃+* L)

Tactic:
obtain ⟨e⟩ := Cardinal.lift_mk_eq'.1 this

Result:
case intro.intro.intro
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝¹ : Algebra (ZMod p) K := ZMod.algebra K p
this✝ : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
hL : ℵ₀ < #L
this : Cardinal.lift.{v, u} #↑s = Cardinal.lift.{u, v} #↑t
e : ↑s ≃ ↑t
⊢ Nonempty (K ≃+* L)

Proof state:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
⊢ ℵ₀ < #L

Tactic:
rwa [← aleph0_lt_lift.{v, u}, ← lift_mk_eq'.2 hKL, aleph0_lt_lift]

Result:
no goals

Proof state:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
hL : ℵ₀ < #L
⊢ Cardinal.lift.{v, u} #↑s = Cardinal.lift.{u, v} #↑t

Tactic:
rw [← lift_injective (cardinal_eq_cardinal_transcendence_basis_of_aleph0_lt _
    hs (le_of_lt (lt_aleph0_of_finite _)) hK),
  ← lift_injective (cardinal_eq_cardinal_transcendence_basis_of_aleph0_lt _
    ht (le_of_lt (lt_aleph0_of_finite _)) hL)]

Result:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
hL : ℵ₀ < #L
⊢ Cardinal.lift.{v, u} #K = Cardinal.lift.{u, v} #L

Proof state:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
⊢ Nonempty (K ≃+* L)

Tactic:
letI : Algebra (ZMod p) K := ZMod.algebra _ _

Result:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this : Algebra (ZMod p) K := ZMod.algebra K p
⊢ Nonempty (K ≃+* L)

Proof state:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
⊢ Nonempty (K ≃+* L)

Tactic:
obtain ⟨s, hs⟩ := exists_isTranscendenceBasis (ZMod p)
  (show Function.Injective (algebraMap (ZMod p) K) from RingHom.injective _)

Result:
case intro
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
⊢ Nonempty (K ≃+* L)

Proof state:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this : Algebra (ZMod p) K := ZMod.algebra K p
⊢ Nonempty (K ≃+* L)

Tactic:
letI : Algebra (ZMod p) L := ZMod.algebra _ _

Result:
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝ : Algebra (ZMod p) K := ZMod.algebra K p
this : Algebra (ZMod p) L := ZMod.algebra L p
⊢ Nonempty (K ≃+* L)

Proof state:
case intro.intro.intro
K : Type u
L : Type v
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : IsAlgClosed K
inst✝³ : IsAlgClosed L
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP K p
inst✝ : CharP L p
hK : ℵ₀ < #K
hKL : Nonempty (K ≃ L)
this✝¹ : Algebra (ZMod p) K := ZMod.algebra K p
this✝ : Algebra (ZMod p) L := ZMod.algebra L p
s : Set K
hs : IsTranscendenceBasis (ZMod p) Subtype.val
t : Set L
ht : IsTranscendenceBasis (ZMod p) Subtype.val
hL : ℵ₀ < #L
this : Cardinal.lift.{v, u} #↑s = Cardinal.lift.{u, v} #↑t
e : ↑s ≃ ↑t
⊢ Nonempty (K ≃+* L)

Tactic:
exact ⟨equivOfTranscendenceBasis _ _ e hs ht⟩

Result:
no goals