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Project-declaredLean 4.31.0 · mathlib@fabf563a

Prop3d4₀func defprop2

HarderNarasimhan.impl.prop3d4₀func_defprop2

Plain-language statement

Another key property of the recursion: step i+1 is chosen to be “maximal among those with at least its μA-value”, in the sense that no z strictly between step i+1 and step i can have μA (I.left, z) greater-or-equal to μA (I.left, step(i+1)). This is a tie-breaking/optimality condition derived from minimality in the well-founded has_min cho...

Exact Lean statement

lemma prop3d4₀func_defprop2
{ℒ : Type*} [Nontrivial ℒ] [Lattice ℒ] [BoundedOrder ℒ] [inst_3 : WellFoundedGT ℒ]
{S : Type*} [CompleteLattice S]
(μ : {p :ℒ × ℒ // p.1 < p.2} → S)
(I : {p : ℒ × ℒ // p.1 < p.2})
(i : ℕ) (hi : I.val.1 ≠ (prop3d4₀func μ I (i + 1)).val) :
∀ z : ℒ, (hz : (prop3d4₀func μ I (i+1)).val < z ∧ z ≤ (prop3d4₀func μ I i).val) →
    ¬ μA μ ⟨(I.val.1, z),lt_of_le_of_lt (prop3d4₀func μ I (i+1)).prop.1 hz.1⟩ ≥
      μA μ ⟨(I.val.1 , (prop3d4₀func μ I (i+1)).val) ,
        lt_of_le_of_ne (prop3d4₀func μ I (i+1)).prop.1 hi⟩

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
lemma prop3d4₀func_defprop2{ℒ : Type*} [Nontrivial ℒ] [Lattice ℒ] [BoundedOrder ℒ] [inst_3 : WellFoundedGT ℒ]{S : Type*} [CompleteLattice S](μ : {p :ℒ × ℒ // p.1 < p.2}  S)(I : {p : ℒ × ℒ // p.1 < p.2})(i : ) (hi : I.val.1  (prop3d4₀func μ I (i + 1)).val) : z : ℒ, (hz : (prop3d4₀func μ I (i+1)).val < z  z  (prop3d4₀func μ I i).val)     ¬ μA μ (I.val.1, z),lt_of_le_of_lt (prop3d4₀func μ I (i+1)).prop.1 hz.1       μA μ (I.val.1 , (prop3d4₀func μ I (i+1)).val) ,        lt_of_le_of_ne (prop3d4₀func μ I (i+1)).prop.1 hi := by  intro z hz  simp only [prop3d4₀func, prop3d4₀func_helper μ I i hi]  have hne : (ℒₛ μ I (prop3d4₀func μ I i) <| prop3d4₀func_helper μ I i hi).Nonempty := by    by_contra hcontra    simp only [prop3d4₀func, prop3d4₀func_helper μ I i hi, hcontra] at hi    simp only [↓reduceDIte, ne_eq, not_true_eq_false] at hi  simp only [hne]  by_contra hcontra  have h' : z  (ℒₛ μ I (prop3d4₀func μ I i) <| prop3d4₀func_helper μ I i hi) := by    use le_of_lt <| lt_of_le_of_lt (prop3d4₀func μ I (i + 1)).prop.1 hz.1,      le_trans hz.2 (prop3d4₀func μ I i).prop.2    have h'' : z < (prop3d4₀func μ I i).val := by      apply lt_of_le_of_ne hz.2      by_contra hcontra'      simp only [hcontra', ↓reduceDIte, ge_iff_le] at hcontra      exact (inst_3.wf.has_min (ℒₛ μ I (prop3d4₀func μ I i) <| prop3d4₀func_helper μ I i hi) hne        ).choose_spec.1.out.choose_spec.choose_spec.not_ge hcontra    use ne_of_lt <| lt_of_le_of_lt (prop3d4₀func μ I (i+1)).prop.1 hz.1,h'', lt_of_le_of_lt'      hcontra.ge (inst_3.wf.has_min (ℒₛ μ I (prop3d4₀func μ I i) <| prop3d4₀func_helper μ I i hi)      hne).choose_spec.1.out.choose_spec.choose_spec  simp only [prop3d4₀func, prop3d4₀func_helper μ I i hi, hne] at hz  exact (inst_3.wf.has_min (ℒₛ μ I (prop3d4₀func μ I i) <| prop3d4₀func_helper μ I i hi) hne    ).choose_spec.2 z h' hz.1
Project
Harder-Narasimhan
License
Apache-2.0
Commit
20220e90b72c
Source
HarderNarasimhan/Semistability/Impl.lean:187-219

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Related declarations

Project-declaredLean 4.31.0

Associated Primes ker mk Linear Map eq

HarderNarasimhan.CommutativeAlgebra.associatedPrimes_ker_mkLinearMap_eq

Project documentation

Associated primes of the kernel of the localization map. This identifies the associated primes of ker (LocalizedModule.mkLinearMap S M) : Submodule R M with the associated primes of M that do meet the multiplicative set S. Equivalently, these are the associated primes of M after removing those disjoint from S. This lemma is used as the “kernel...

algebraic geometryvector bundlescategory theory

Source project: Harder-Narasimhan

Person-level attribution pending.

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Project-declaredLean 4.31.0

Associated Primes ker mk Linear Map subset

HarderNarasimhan.CommutativeAlgebra.associatedPrimes_ker_mkLinearMap_subset

Plain-language statement

One-sided inclusion for associated primes of the kernel of the localization map. If p ∈ associatedPrimes R (ker (mkLinearMap S M)), then p is an associated prime of M and p is not disjoint from the multiplicative set S. This is one direction of associatedPrimes_ker_mkLinearMap_eq.

algebraic geometryvector bundlescategory theory

Source project: Harder-Narasimhan

Person-level attribution pending.

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Project-declaredLean 4.31.0

Associated Primes localized Module subset disjoint

HarderNarasimhan.CommutativeAlgebra.associatedPrimes_localizedModule_subset_disjoint

Plain-language statement

Associated primes of a localized module are disjoint from the multiplicative set. More precisely, if p ∈ associatedPrimes R (LocalizedModule S M), then p.carrier ∩ S = ∅. This is a standard fact in commutative algebra: an element of S becomes a unit after localization, so no associated prime of the localized module can contain an element of S.

algebraic geometryvector bundlescategory theory

Source project: Harder-Narasimhan

Person-level attribution pending.

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