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Project-declaredLean 4.31.0 · mathlib@fabf563a

JHFil refine lt step payoff

HarderNarasimhan.impl.JHFil_refine_lt_step_payoff

Plain-language statement

JHFil_refine_lt_step_payoff proves the stability step condition for the chain JHFil. For each k with JHFil ... k > ⊥ and any strict intermediate z between JHFil ... (k+1) and JHFil ... k, the payoff strictly decreases when refining the step through z.

Exact Lean statement

lemma JHFil_refine_lt_step_payoff
{ℒ : Type*} [Nontrivial ℒ] [Lattice ℒ] [BoundedOrder ℒ] [hacc : WellFoundedGT ℒ]
{S : Type*} [CompleteLinearOrder S]
(μ : {p : ℒ × ℒ // p.1 < p.2} → S) [hwdcc' : StrongDescendingChainCondition' μ]
(hμ : μ ⟨(⊥, ⊤), bot_lt_top⟩ ≠ ⊤)
(hμsl : SlopeLike μ) (hst : Semistable μ)
(hdc : ∀ x : ℕ → ℒ, (sax : StrictAnti x) → ∃ N : ℕ, μ ⟨(x (N +1), x N), sax <| lt_add_one N⟩ = ⊤) :
∀ k : ℕ,  (hk : JHFil μ hμ hμsl hst hdc k > ⊥) → ∀ z : ℒ, (h' : JHFil μ hμ hμsl hst hdc (k + 1) < z)
  → (h'' : z < JHFil μ hμ hμsl hst hdc k) →
  μ ⟨(JHFil μ hμ hμsl hst hdc (k + 1), z), h'⟩ < μ ⟨(JHFil μ hμ hμsl hst hdc (k + 1),
    JHFil μ hμ hμsl hst hdc k), JHFil_anti_mono μ hμ hμsl hst hdc k hk⟩

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
lemma JHFil_refine_lt_step_payoff{ℒ : Type*} [Nontrivial ℒ] [Lattice ℒ] [BoundedOrder ℒ] [hacc : WellFoundedGT ℒ]{S : Type*} [CompleteLinearOrder S](μ : {p : ℒ × ℒ // p.1 < p.2}  S) [hwdcc' : StrongDescendingChainCondition' μ](hμ : μ (⊥, ⊤), bot_lt_top  ⊤)(hμsl : SlopeLike μ) (hst : Semistable μ)(hdc :  x :   ℒ, (sax : StrictAnti x)   N : , μ (x (N +1), x N), sax <| lt_add_one N = ⊤) : k : ,  (hk : JHFil μ hμ hμsl hst hdc k > ⊥)   z : ℒ, (h' : JHFil μ hμ hμsl hst hdc (k + 1) < z)   (h'' : z < JHFil μ hμ hμsl hst hdc k)   μ (JHFil μ hμ hμsl hst hdc (k + 1), z), h' < μ (JHFil μ hμ hμsl hst hdc (k + 1),    JHFil μ hμ hμsl hst hdc k), JHFil_anti_mono μ hμ hμsl hst hdc k hk := by  intro k hk z h' h''  have this_new : Semistable μ  μmax μ TotIntvl = μ TotIntvl :=    fun a  (List.TFAE.out (impl.thm4d21 μ hμsl inferInstance inferInstance).1 0 3).2      ((impl.thm4d21 μ hμsl inferInstance inferInstance).2.1 a)  specialize this_new hst  simp only [μmax, TotIntvl, ne_eq] at this_new  have this_q: μ (⊥, z), lt_of_le_of_lt bot_le h'  μ (⊥, ⊤), bot_lt_top := by    rw [ this_new]    exact le_sSup z, in_TotIntvl z,      Ne.symm <| bot_lt_iff_ne_bot.1 <| lt_of_le_of_lt bot_le h', rfl  by_cases hfp1bot : JHFil μ hμ hμsl hst hdc (k + 1) =  · simp only [hfp1bot]    have : ¬ {p |  (h : ⊥ < p), p < JHFil μ hμ hμsl hst hdc k  μ (⊥, p), h =      μ (⊥, ⊤), bot_lt_top}.Nonempty := by      by_contra!      simp only [JHFil,this] at hfp1bot      have := (hacc.wf.has_min _ this).choose_spec.1.out.choose      simp only [↓reduceDIte, exists_and_left, Set.mem_setOf_eq, and_imp,        forall_exists_index] at hfp1bot      simp only [exists_and_left, Set.mem_setOf_eq, and_imp, forall_exists_index] at this      exact (ne_of_lt this) hfp1bot.symm    apply Set.not_nonempty_iff_eq_empty.1 at this    apply Set.eq_empty_iff_forall_notMem.1 at this    specialize this z    simp only [exists_and_left, Set.mem_setOf_eq, not_and, not_exists] at this    replace := lt_of_le_of_ne this_q <| this h'' (lt_of_le_of_lt bot_le h')    by_cases hk' : k = 0    · simpa only [hk',JHFil]    · conv_rhs =>        arg 1; arg 1; arg 2; arg 6        rw [ Nat.sub_one_add_one hk']      have hne : {p |  (h : ⊥ < p), p < JHFil μ hμ hμsl hst hdc (k - 1)  μ (⊥, p), h =        μ (⊥, ⊤), bot_lt_top}.Nonempty := by        by_contra!        have this': JHFil μ hμ hμsl hst hdc k = JHFil μ hμ hμsl hst hdc ((k-1)+1) := by          conv_lhs =>            arg 6            rw [ Nat.sub_one_add_one hk']        simp only [this',JHFil,this] at hk        simp only [Set.not_nonempty_empty, ↓reduceDIte, gt_iff_lt, lt_self_iff_false] at hk      rw [ (hacc.wf.has_min _ hne).choose_spec.1.out.2.2] at this      simp only [JHFil,hne]      simp only [↓reduceDIte, exists_and_left, Set.mem_setOf_eq, gt_iff_lt, and_imp,        forall_exists_index]      simpa only [exists_and_left, Set.mem_setOf_eq,        gt_iff_lt, and_imp, forall_exists_index] using this  · have h''' : μ (⊥, z), lt_of_le_of_lt bot_le h' < μ (⊥, ⊤), bot_lt_top := by      refine lt_of_le_of_ne this_q ?_      by_contra!      by_cases hne : {p |  (h : ⊥ < p), p < JHFil μ hμ hμsl hst hdc k         μ (⊥, p), h = μ (⊥, ⊤), bot_lt_top}.Nonempty      · have := (hacc.wf.has_min _ hne).choose_spec.2 z (by use lt_of_le_of_lt bot_le h')        simp only [JHFil,hne] at h'        simp only [gt_iff_lt, exists_and_left, Set.mem_setOf_eq, and_imp, forall_exists_index,          ↓reduceDIte] at *        exact this h'      · refine hne ?_        use z, lt_of_le_of_lt bot_le h'    have h'''' : μ (⊥, ⊤), bot_lt_top = μ (⊥, JHFil μ hμ hμsl hst hdc (k + 1)),      bot_lt_iff_ne_bot.2 hfp1bot := by      by_cases hne : {p |  (h : ⊥ < p), p < JHFil μ hμ hμsl hst hdc k  μ (⊥, p), h =        μ (⊥, ⊤), bot_lt_top}.Nonempty      · simp only [JHFil,hne]        have := (hacc.wf.has_min _ hne).choose_spec.1.out.choose_spec.2        simp only [gt_iff_lt, exists_and_left, Set.mem_setOf_eq, and_imp, forall_exists_index,          ↓reduceDIte] at *        exact this.symm      · simp only [JHFil,hne] at hfp1bot        simp only [↓reduceDIte, not_true_eq_false] at hfp1bot    exact (JHFil_step_payoff_eq_tot μ hμ hμsl hst hdc k hk).symm ▸ lt_trans ((Or.resolve_right <|      (Or.resolve_left <| (impl.prop4d6 μ).1 hμsl ⊥ (JHFil μ hμ hμsl hst hdc (k + 1)) z      bot_lt_iff_ne_bot.2 hfp1bot,h') (not_and_iff_not_or_not.2 <| Or.inl <| not_lt_of_gt <|      h'''' ▸ h''')) (not_and_iff_not_or_not.2 <| Or.inl <| ne_of_gt <| h'''' ▸ h''')).2 h'''
Project
Harder-Narasimhan
License
Apache-2.0
Commit
20220e90b72c
Source
HarderNarasimhan/JordanHolderFiltration/Impl.lean:252-335

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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...

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Project-declaredLean 4.31.0

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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

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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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