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chore(RingTheory/Ideal/KrullsHeightTheorem): fix capitalization of minimalPrimes (#37463)
Fixed capitalization convention for `minimal_prime` to lower camel case `minimalPrime` according to mathlib naming conventions. There is one changed lemma in `RingTheory/Ideal/KrullsHeightTheorem` and one in `RingTheory/Ideal/MinimalPrime/Localization`.
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Mathlib/RingTheory/Ideal/KrullsHeightTheorem.lean

Lines changed: 11 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,7 @@ In this file, we prove **Krull's principal ideal theorem** (also known as
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that: In a commutative Noetherian ring `R`, any prime ideal that is minimal over a principal ideal
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has height at most 1.
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* `Ideal.height_le_spanRank_toENat_of_mem_minimal_primes` : This theorem is the
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* `Ideal.height_le_spanRank_toENat_of_mem_minimalPrimes` : This theorem is the
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**Krull's height theorem** (also known as **Krullscher Höhensatz**), which states that:
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In a commutative Noetherian ring `R`, any prime ideal that is minimal over an ideal generated by
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`n` elements has height at most `n`.
@@ -36,7 +36,7 @@ In this file, we prove **Krull's principal ideal theorem** (also known as
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a (finitely-generated) ideal is smaller than or equal to the minimum number of generators for
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this ideal.
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* `Ideal.height_le_iff_exists_minimal_primes` : In a commutative Noetherian ring `R`, a prime ideal
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* `Ideal.height_le_iff_exists_minimalPrimes` : In a commutative Noetherian ring `R`, a prime ideal
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`p` has height no greater than `n` if and only if it is a minimal ideal over some ideal generated
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by no more than `n` elements.
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-/
@@ -148,7 +148,7 @@ theorem Ideal.mem_minimalPrimes_span_of_mem_minimalPrimes_span_insert {q p : Ide
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rw [height_eq_primeHeight] at h
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have := (primeHeight_strict_mono h_lt).trans_le h
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rw [ENat.lt_one_iff_eq_zero, primeHeight_eq_zero_iff] at this
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have := minimal_primes_comap_of_surjective hf this
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have := minimalPrimes_comap_of_surjective hf this
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rwa [comap_map_of_surjective f hf, ← RingHom.ker_eq_comap_bot,
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mk_ker, sup_eq_left.mpr hI'q] at this
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refine height_le_one_of_isPrincipal_of_mem_minimalPrimes ((span {x}).map f) (p.map f) ⟨⟨this,
@@ -167,7 +167,7 @@ open IsLocalRing in
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/-- **Krull's height theorem** (also known as **Krullscher Höhensatz**) :
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In a commutative Noetherian ring `R`, any prime ideal that is minimal over an ideal generated
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by `n` elements has height at most `n`. -/
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nonrec lemma Ideal.height_le_spanRank_toENat_of_mem_minimal_primes
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nonrec lemma Ideal.height_le_spanRank_toENat_of_mem_minimalPrimes
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(I : Ideal R) (p : Ideal R) (hp : p ∈ I.minimalPrimes) :
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p.height ≤ I.spanRank.toENat := by
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classical
@@ -219,11 +219,14 @@ nonrec lemma Ideal.height_le_spanRank_toENat_of_mem_minimal_primes
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refine hspan.trans <| radical_mono ?_
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rw [← Set.union_singleton, span_union]
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@[deprecated (since := "2026-04-01")] alias Ideal.height_le_spanRank_toENat_of_mem_minimal_primes :=
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Ideal.height_le_spanRank_toENat_of_mem_minimalPrimes
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lemma Ideal.height_le_card_of_mem_minimalPrimes_span_finset {p : Ideal R} {s : Finset R}
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(hI : p ∈ (Ideal.span s).minimalPrimes) :
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p.height ≤ s.card := by
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trans (Cardinal.toENat (Submodule.spanRank (Ideal.span (s : Set R))))
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· exact Ideal.height_le_spanRank_toENat_of_mem_minimal_primes _ _ hI
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· exact Ideal.height_le_spanRank_toENat_of_mem_minimalPrimes _ _ hI
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· simpa using Submodule.spanRank_span_le_card (s : Set R)
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lemma Ideal.height_le_card_of_mem_minimalPrimes_span {p : Ideal R} {s : Set R}
@@ -238,7 +241,7 @@ lemma Ideal.height_le_spanRank_toENat (I : Ideal R) (hI : I ≠ ⊤) :
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I.height ≤ I.spanRank.toENat := by
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obtain ⟨J, hJ⟩ := nonempty_minimalPrimes hI
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refine (iInf₂_le J hJ).trans ?_
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convert (I.height_le_spanRank_toENat_of_mem_minimal_primes J hJ)
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convert (I.height_le_spanRank_toENat_of_mem_minimalPrimes J hJ)
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exact Eq.symm (@height_eq_primeHeight _ _ J hJ.1.1)
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lemma Ideal.height_le_spanFinrank (I : Ideal R) (hI : I ≠ ⊤) :
@@ -291,7 +294,7 @@ lemma Ideal.height_le_iff_exists_minimalPrimes (p : Ideal R) [p.IsPrime]
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norm_cast
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· rintro ⟨I, hp, hI⟩
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exact le_trans
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(Ideal.height_le_spanRank_toENat_of_mem_minimal_primes I p hp)
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(Ideal.height_le_spanRank_toENat_of_mem_minimalPrimes I p hp)
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(by simpa using (Cardinal.toENat.monotone' hI))
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/-- If `p` is a prime in a Noetherian ring `R`, there exists a `p`-primary ideal `I`
@@ -308,7 +311,7 @@ lemma Ideal.exists_finset_card_eq_height_of_isNoetherianRing (p : Ideal R) [p.Is
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· convert_to p.height ≤ I.spanRank.toENat
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· symm
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simpa [Submodule.fg_iff_spanRank_eq_spanFinrank] using (IsNoetherian.noetherian I)
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· exact I.height_le_spanRank_toENat_of_mem_minimal_primes _ hI
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· exact I.height_le_spanRank_toENat_of_mem_minimalPrimes _ hI
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/-- If `I ≤ p` and `p` is prime, the height of `p` is bounded by the height of `p ⧸ I R` plus
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the span rank of `I`. -/

Mathlib/RingTheory/Ideal/MinimalPrime/Localization.lean

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -127,7 +127,7 @@ section
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variable {R S : Type*} [CommRing R] [CommRing S] {I J : Ideal R}
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theorem Ideal.minimal_primes_comap_of_surjective {f : R →+* S} (hf : Function.Surjective f)
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theorem Ideal.minimalPrimes_comap_of_surjective {f : R →+* S} (hf : Function.Surjective f)
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{I J : Ideal S} (h : J ∈ I.minimalPrimes) : J.comap f ∈ (I.comap f).minimalPrimes := by
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have := h.1.1
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refine ⟨⟨inferInstance, Ideal.comap_mono h.1.2⟩, ?_⟩
@@ -139,6 +139,9 @@ theorem Ideal.minimal_primes_comap_of_surjective {f : R →+* S} (hf : Function.
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· exact ⟨Ideal.map_isPrime_of_surjective hf this, Ideal.le_map_of_comap_le_of_surjective f hf e₁⟩
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· exact Ideal.map_le_of_le_comap e₂
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@[deprecated (since := "2026-04-01")] alias Ideal.minimal_primes_comap_of_surjective :=
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Ideal.minimalPrimes_comap_of_surjective
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theorem Ideal.comap_minimalPrimes_eq_of_surjective {f : R →+* S} (hf : Function.Surjective f)
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(I : Ideal S) : (I.comap f).minimalPrimes = Ideal.comap f '' I.minimalPrimes := by
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ext J
@@ -147,7 +150,7 @@ theorem Ideal.comap_minimalPrimes_eq_of_surjective {f : R →+* S} (hf : Functio
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obtain ⟨p, h, rfl⟩ := Ideal.exists_minimalPrimes_comap_eq f J H
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exact ⟨p, h, rfl⟩
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· rintro ⟨J, hJ, rfl⟩
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exact Ideal.minimal_primes_comap_of_surjective hf hJ
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exact Ideal.minimalPrimes_comap_of_surjective hf hJ
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lemma Ideal.minimalPrimes_map_of_surjective {S : Type*} [CommRing S] {f : R →+* S}
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(hf : Function.Surjective f) (I : Ideal R) :

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