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Project-declaredLean 4.31.0 · mathlib@fabf563a

Rmk2d5₂

HarderNarasimhan.impl.rmk2d5₂

Plain-language statement

Remark 2.5 (part 2): idempotence of μmax. The statement μmax μ I = μmax (μmax μ) I says that applying μmax twice does not change the result. Convexity is used to relate the two suprema.

Exact Lean statement

lemma rmk2d5₂
  (I : {p : ℒ × ℒ // p.1 < p.2})
  (μ : {p :ℒ × ℒ // p.1 < p.2} → S) (hμcvx : ConvexI I μ) :
  μmax μ I = μmax (μmax μ) I

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
lemma rmk2d5₂  (I : {p : ℒ × ℒ // p.1 < p.2})  (μ : {p :ℒ × ℒ // p.1 < p.2}  S) (hμcvx : ConvexI I μ) :  μmax μ I = μmax (μmax μ) I := by  apply eq_of_le_of_ge  · apply le_sSup    use I.val.2, ⟨⟨le_of_lt I.prop, le_refl I.val.2, ne_of_lt I.prop  · apply sSup_le    simp only [ne_eq, Set.mem_setOf_eq, forall_exists_index]    intro b v hv res    rw [ res]    have h : μmax μ (v ⊓ I.val.1, v), inf_lt_left.2 (not_le_of_gt (lt_of_le_of_ne hv.1.1 hv.2))       μmax μ (I.val.1, I.val.2),        lt_of_le_of_lt' ((sup_eq_left.2 hv.1.1).symm ▸ hv.1.2)          <| right_lt_sup.2 <| not_le_of_gt <| lt_of_le_of_ne hv.1.1 hv.2 :=      lem2d4₂I I μ hμcvx v hv.1 I.val.1 le_rfl, le_of_lt I.prop (not_le_of_gt <|        lt_of_le_of_ne hv.1.1 hv.2) I.val.2 <| (sup_eq_left.2 hv.1.1).symm ▸ hv.1.2    simp only [inf_eq_right.2 hv.1.1] at h    exact h
Project
Harder-Narasimhan
License
Apache-2.0
Commit
20220e90b72c
Source
HarderNarasimhan/Convexity/Impl.lean:233-251

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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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