Plain-language statement
Paper Lemma 2.4 (part 2) localized to an interval I. Assuming convexity of μ on I, this gives a bound between two μmax values obtained from a non-comparable pair x,w. API note: the conclusion is stated as an inequality between μmax on two strict pairs in ℒ.
Exact Lean statement
lemma lem2d4₂I
(I : {p : ℒ × ℒ // p.1 < p.2})
(μ : {p :ℒ × ℒ // p.1 < p.2} → S) (hμcvx : ConvexI I μ)
(x : ℒ) (hxI : InIntvl I x)
(w : ℒ) (hwI : InIntvl I w)
(hxw : ¬ x ≤ w)
(t : ℒ)
(hxwt : x ⊔ w ≤ t) :
μmax μ ⟨(x ⊓ w, x), inf_lt_left.2 hxw⟩ ≤
μmax μ ⟨(w, t), lt_of_le_of_lt' hxwt <| right_lt_sup.2 hxw⟩Formal artifact
Lean source
lemma lem2d4₂I (I : {p : ℒ × ℒ // p.1 < p.2}) (μ : {p :ℒ × ℒ // p.1 < p.2} → S) (hμcvx : ConvexI I μ) (x : ℒ) (hxI : InIntvl I x) (w : ℒ) (hwI : InIntvl I w) (hxw : ¬ x ≤ w) (t : ℒ) (hxwt : x ⊔ w ≤ t) : μmax μ ⟨(x ⊓ w, x), inf_lt_left.2 hxw⟩ ≤ μmax μ ⟨(w, t), lt_of_le_of_lt' hxwt <| right_lt_sup.2 hxw⟩ := by let target := μmax μ ⟨(w, t), lt_of_le_of_lt' hxwt <| right_lt_sup.2 hxw⟩ have h : ∀ b : ℒ, (h' : x ⊓ w < b ∧ b ≤ x) → μ ⟨(x ⊓ w, b), h'.1⟩ ≤ target := by intro b hb have hh : x ⊓ w = b ⊓ w := by refine le_antisymm ?_ <| inf_le_inf_right w hb.2 nth_rw 1 [← inf_idem w, ← inf_assoc] exact inf_le_inf_right w <| le_of_lt hb.1 simp only [hh, ge_iff_le] have hbnlew : ¬ b ≤ w := inf_lt_left.mp ((congrArg (fun _a ↦ _a < b) (hh.symm)) ▸ hb.1) have hfinal : μ ⟨(w, b ⊔ w), right_lt_sup.mpr hbnlew⟩ ≤ target := by apply le_sSup use b ⊔ w, ⟨⟨le_sup_right, le_trans (sup_le_sup_right hb.2 w) hxwt⟩, (mt right_eq_sup.1) <| inf_lt_left.1 <| hh.symm ▸ hb.1⟩ apply le_trans (hμcvx.convex b w ⟨le_of_lt (lt_of_le_of_lt (le_inf hxI.1 hwI.1) hb.1), le_trans hb.2 hxI.2⟩ hwI hbnlew) hfinal apply sSup_le rintro b ⟨w_1, ⟨hf₁, hf₂⟩⟩ rw [hf₂.symm] exact h w_1 ⟨lt_of_le_of_ne hf₁.1.1 hf₁.2, hf₁.1.2⟩- Project
- Harder-Narasimhan
- License
- Apache-2.0
- Commit
- 20220e90b72c
- Source
- HarderNarasimhan/Convexity/Impl.lean:131-160
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Related declarations
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...
Source project: Harder-Narasimhan
Person-level attribution pending.
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.
Source project: Harder-Narasimhan
Person-level attribution pending.
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.
Source project: Harder-Narasimhan
Person-level attribution pending.