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Merge pull request #36 from GTBarkley/sayantan

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new: Made some progress on the isField.dim_zero lemma
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Sayantan Santra 2023-06-13 02:00:39 -05:00 committed by GitHub
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1 changed files with 13 additions and 3 deletions
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CommAlg/sayantan.lean
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@ -57,9 +57,19 @@ lemma isField.dim_zero {D: Type _} [CommRing D] [IsDomain D] (h: krullDim D = 0)
simp [height] at h simp [height] at h
by_contra x by_contra x
rw [Ring.not_isField_iff_exists_prime] at x rw [Ring.not_isField_iff_exists_prime] at x
obtain ⟨P, ⟨h, primeP⟩⟩ := x obtain ⟨P, ⟨h1, primeP⟩⟩ := x
have PgtBot : P > ⊥ := Ne.bot_lt h have PgtBot : P > ⊥ := Ne.bot_lt h1
have pos_height : ↑(Set.chainHeight {J | J < P}) > 0 := by
have : ⊥ ∈ {J | J < P} := PgtBot
have : {J | J < P}.Nonempty := Set.nonempty_of_mem this
-- have : {J | J < P} ≠ ∅ := Set.Nonempty.ne_empty this
rw [←Set.one_le_chainHeight_iff] at this
exact Iff.mp ENat.one_le_iff_pos this
have zero_height : ↑(Set.chainHeight {J | J < P}) = 0 := by
-- Probably need to use Sup_le or something here
sorry sorry
have : ↑(Set.chainHeight {J | J < P}) ≠ 0 := Iff.mp pos_iff_ne_zero pos_height
contradiction
lemma dim_eq_zero_iff_field {D: Type _} [CommRing D] [IsDomain D] : krullDim D = 0 ↔ IsField D := by lemma dim_eq_zero_iff_field {D: Type _} [CommRing D] [IsDomain D] : krullDim D = 0 ↔ IsField D := by
constructor constructor