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[Merged by Bors] - feat: a function with vanishing integral against smooth functions supported in U is ae zero in U #8805

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@alreadydone alreadydone commented Dec 4, 2023

A stronger version of #8800, the differences are:

  • assume either IsSigmaCompact U or SigmaCompactSpace M;

  • only need test functions satisfying tsupport g ⊆ U rather than support g ⊆ U;

  • requires LocallyIntegrableOn U rather than LocallyIntegrable on the whole space.

Also fills in some missing APIs around the manifold and measure theory libraries.


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@alreadydone alreadydone added awaiting-review The author would like community review of the PR t-analysis Analysis (normed *, calculus) t-measure-probability Measure theory / Probability theory labels Dec 4, 2023
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Looks very good, thanks!

Mathlib/Analysis/Distribution/AEEqOfIntegralContDiff.lean Outdated Show resolved Hide resolved
intro g g_smth g_supp
classical
have cpt := g_supp.image continuous_induced_dom
let g' x := if hx : x ∈ U then g ⟨x, hx⟩ else 0
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Could you instead define g' as Function.extend Subtype.val g 0, and prove in separate lemmas that the extension of a smooth compactly supported function is smooth and compactly supported?

@alreadydone alreadydone added awaiting-author A reviewer has asked the author a question or requested changes and removed awaiting-review The author would like community review of the PR labels Dec 4, 2023
Comment on lines +545 to +570
theorem liftPropAt_iff_comp_subtype_val (hG : LocalInvariantProp G G' P) {U : Opens M}
(f : M → M') (x : U) :
LiftPropAt P f x ↔ LiftPropAt P (f ∘ Subtype.val) x := by
congrm ?_ ∧ ?_
· simp_rw [continuousWithinAt_univ, U.openEmbedding'.continuousAt_iff]
· apply hG.congr_iff
exact (U.chartAt_subtype_val_symm_eventuallyEq).fun_comp (chartAt H' (f x) ∘ f)

theorem liftPropAt_iff_comp_inclusion (hG : LocalInvariantProp G G' P) {U V : Opens M} (hUV : U ≤ V)
(f : V → M') (x : U) :
LiftPropAt P f (Set.inclusion hUV x) ↔ LiftPropAt P (f ∘ Set.inclusion hUV : U → M') x := by
congrm ?_ ∧ ?_
· simp [continuousWithinAt_univ,
· simp_rw [continuousWithinAt_univ,
(TopologicalSpace.Opens.openEmbedding_of_le hUV).continuousAt_iff]
· apply hG.congr_iff
exact (TopologicalSpace.Opens.chartAt_inclusion_symm_eventuallyEq hUV).fun_comp
(chartAt H' (f (Set.inclusion hUV x)) ∘ f)
#align structure_groupoid.local_invariant_prop.lift_prop_at_iff_comp_inclusion StructureGroupoid.LocalInvariantProp.liftPropAt_iff_comp_inclusion

theorem liftProp_subtype_val {Q : (H → H) → Set H → H → Prop} (hG : LocalInvariantProp G G Q)
(hQ : ∀ y, Q id univ y) (U : Opens M) :
LiftProp Q (Subtype.val : U → M) := by
intro x
show LiftPropAt Q (id ∘ Subtype.val) x
rw [← hG.liftPropAt_iff_comp_subtype_val]
apply hG.liftProp_id hQ
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cc author of #19416 @hrmacbeth in case I'm missing some easy way to deduce smooth_subtype_iff.

@alreadydone alreadydone added awaiting-review The author would like community review of the PR and removed awaiting-author A reviewer has asked the author a question or requested changes labels Dec 6, 2023
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sgouezel commented Dec 7, 2023

bors r+
Thanks!

@github-actions github-actions bot added ready-to-merge This PR has been sent to bors. and removed awaiting-review The author would like community review of the PR labels Dec 7, 2023
mathlib-bors bot pushed a commit that referenced this pull request Dec 7, 2023
…ported in U is ae zero in U (#8805)

A stronger version of #8800, the differences are:

+ assume either `IsSigmaCompact U` or `SigmaCompactSpace M`;

+ only need test functions satisfying `tsupport g ⊆ U` rather than `support g ⊆ U`;

+ requires `LocallyIntegrableOn` U rather than `LocallyIntegrable` on the whole space.

Also fills in some missing APIs around the manifold and measure theory libraries.



Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr>
Co-authored-by: Junyan Xu <junyanxu.math@gmail.com>
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mathlib-bors bot commented Dec 7, 2023

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat: a function with vanishing integral against smooth functions supported in U is ae zero in U [Merged by Bors] - feat: a function with vanishing integral against smooth functions supported in U is ae zero in U Dec 7, 2023
@mathlib-bors mathlib-bors bot closed this Dec 7, 2023
@mathlib-bors mathlib-bors bot deleted the jyxu_ae_eq branch December 7, 2023 09:17
awueth pushed a commit that referenced this pull request Dec 19, 2023
…ported in U is ae zero in U (#8805)

A stronger version of #8800, the differences are:

+ assume either `IsSigmaCompact U` or `SigmaCompactSpace M`;

+ only need test functions satisfying `tsupport g ⊆ U` rather than `support g ⊆ U`;

+ requires `LocallyIntegrableOn` U rather than `LocallyIntegrable` on the whole space.

Also fills in some missing APIs around the manifold and measure theory libraries.



Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr>
Co-authored-by: Junyan Xu <junyanxu.math@gmail.com>
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