feat(Analysis/Convolution): add convolution_symm, convolution, (3 more lemmas)

[lakesare]

Upstreaming from Carleson: /Carleson/ToMathlib/Analysis/Convolution.lean

---

Changes from the Carleson version

• theorem convolution_symm
  • renamed g to f' (to reuse the existing section variable)
• theorem AEStronglyMeasurable.convolution
  • L was implicit, now became explicit (to comply with existing section variables)
  • changed [SigmaFinite μ] to [SFinite μ] (because it's a weaker requirement /Mathlib/MeasureTheory/Measure/Typeclasses/SFinite.lean#L191)
• lemma lintegral_enorm_convolution_integrand_le_eLpNorm_mul_eLpNorm
  • surrounding theorems in the mathlib file are theorems, however this is specifically a helper lemma, so I left it as a lemma (TODO - correct decision?)
  • removed the comment "/-- This implies both of the following theorems convolutionExists_of_memLp_memLp and enorm_convolution_le_eLpNorm_mul_eLpNorm. -/", because I think such comments are not in mathlib (TODO - correct decision?)
  • L was implicit, now became explicit (same as above)
  • changed [SigmaFinite μ] to [SFinite μ] (same as above)
• theorem ConvolutionExists.of_memLp_memLp
  • L was implicit, now became explicit (same as above)
  • changed [SigmaFinite μ] to [SFinite μ] (same as above)
  • (hf : AEStronglyMeasurable f μ) and (hg : AEStronglyMeasurable g μ) were removed, because we can derive those hypotheses from hfp.aestronglyMeasurable and hgq.aestronglyMeasurable respectively (which we did during refactoring)
• theorem enorm_convolution_le_eLpNorm_mul_eLpNorm
  • L was implicit, now became explicit (same as above)
  • changed [SigmaFinite μ] to [SFinite μ] (same as above)

TODOs

• describe which lemmas were refactored and to what extent
• maybe make (hpq : p.HolderConjugate q) an instance implicit instead

[github-actions]

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[lakesare]

carleson

[github-actions]

PR summary 34cae80a46

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff (regex)

+ AEStronglyMeasurable.convolution
+ ConvolutionExists.of_memLp_memLp
+ convolution_symm
+ enorm_convolution_le_eLpNorm_mul_eLpNorm
+ lintegral_enorm_convolution_integrand_le_eLpNorm_mul_eLpNorm

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

## summary with just the declaration names:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit 34cae80).

• +5 new declarations
• −0 removed declarations

+MeasureTheory.AEStronglyMeasurable.convolution
+MeasureTheory.ConvolutionExists.of_memLp_memLp
+MeasureTheory.convolution_symm
+MeasureTheory.enorm_convolution_le_eLpNorm_mul_eLpNorm
+MeasureTheory.lintegral_enorm_convolution_integrand_le_eLpNorm_mul_eLpNorm

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit 34cae80a46
Reference commit 87a6eccfb8

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/scripts/reporting/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[lakesare]

WIP