Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Hoelder's inequality #942

Merged
merged 13 commits into from
Sep 14, 2023
Merged

Conversation

affeldt-aist
Copy link
Member

@affeldt-aist affeldt-aist commented Jun 3, 2023

Motivation for this change

based on PR #969 (merged)

based on PR #990 (merged, but the use of ^o is still in question)

This PR is already used in the formalization of Minkowski's inequality and might be used in PR #995.

TODO: issue about how to extend Lnorm to handle p = +oo (change Lnorm from R to \bar R?)

TODO: issue about the introduction of a type measureType

@hoheinzollern

Things done/to do
  • added corresponding entries in CHANGELOG_UNRELEASED.md
  • added corresponding documentation in the headers
Compatibility with MathComp 2.0
  • I added the label TODO: HB port to make sure someone ports this PR to
    the hierarchy-builder branch or I already opened an issue or PR (please cross reference).
Automatic note to reviewers

Read this Checklist and put a milestone if possible.

@affeldt-aist affeldt-aist force-pushed the probability_20230603 branch from e6dc7dc to 3b1fd24 Compare June 3, 2023 15:10
@CohenCyril
Copy link
Member

CohenCyril commented Jun 28, 2023

Why is power_pos called like this in the first place ?

Nevermind, I understand why... but shouldn't we call it powR instead? Indeed, on negative bases it would almost give restults in $\mathbb{C}\backslash\mathbb{R}^{-}_{\star}$, except for integer exponents, so it make sense calling it with suffix R.

Ultimately it should be subsumed by a powC function that uses the principal value of the complex log...

@t6s
Copy link
Member

t6s commented Jun 29, 2023

Ultimately it should be subsumed by a powC function that uses the principal value of the complex log...

What is the blocking issue towards that canonical definition? Do we need a theory for analytic continuations, or do we even need Riemann surfaces?

theories/probability.v Outdated Show resolved Hide resolved
@affeldt-aist affeldt-aist mentioned this pull request Jul 6, 2023
3 tasks
@affeldt-aist
Copy link
Member Author

Why is power_pos called like this in the first place ?

Nevermind, I understand why... but shouldn't we call it powR instead? Indeed, on negative bases it would almost give restults in C∖R, except for integer exponents, so it make sense calling it with suffix R.

The renaming is done in PR #969

@affeldt-aist affeldt-aist force-pushed the probability_20230603 branch from d0be959 to d81eca8 Compare July 6, 2023 07:53
@affeldt-aist affeldt-aist added this to the 0.6.4 milestone Jul 6, 2023
@affeldt-aist affeldt-aist force-pushed the probability_20230603 branch 2 times, most recently from cdcd6c6 to 9648cd8 Compare July 20, 2023 11:54
@affeldt-aist affeldt-aist added enhancement ✨ This issue/PR is about adding new features enhancing the library TODO: MC2 port This PR must be ported to mathcomp 2 now that the. Remove this label when the port is done. labels Jul 20, 2023
@affeldt-aist affeldt-aist marked this pull request as ready for review July 20, 2023 11:58
@affeldt-aist affeldt-aist changed the title tentative proof of Hoelder's inequality Hoelder's inequality Jul 20, 2023
Copy link
Contributor

@zstone1 zstone1 left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

One question about the notation. Otherwise the structure looks good.

(mu : {measure set T -> \bar R}).
Local Open Scope ereal_scope.

Definition L_norm (p : R) (f : T -> R) : \bar R :=
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We've talked briefly about this before. But functional analysts abuse this notation with p=0 and p=oo, but they really mean limits in those cases. For what it's worth p=oo is a legitimately useful norm. I have no idea when p=0 is useful. What you prove here is great. You'd need to handle the +oo case separately anyway, so that's fine. The only question for me is about if we want this notation to take arguments in /bar R, and handle +oo and 0 special cases.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We haven't yet decided anything about this comment. Is it blocking?

Copy link
Contributor

@zstone1 zstone1 Aug 9, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

As long as we're fine to maybe change R to \bar R later. Technically it would be a backwards incompatibility, but a very minor one. So I'd say no, not blocking.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We have generalized the definition with the notion of essential supremum so that it handles +oo now. This certainly to be instrumented more with lemmas but we will certainly have an opportunity to go back to it in the near future with the Minkowski PR, Hardy-Littlewood and others.

#[global]
Hint Extern 0 (0 <= L_norm _ _ _) => solve [apply: L_norm_ge0] : core.

Notation "'N[ mu ]_ p [ f ]" := (L_norm mu p f).
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This seems to imply we really need a measureType.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Indeed...

@affeldt-aist affeldt-aist mentioned this pull request Jul 27, 2023
2 tasks
@@ -4,7 +4,7 @@ From mathcomp Require Import all_ssreflect ssralg ssrnum ssrint interval finmap.
From mathcomp Require Import mathcomp_extra boolp classical_sets functions.
From mathcomp Require Import cardinality fsbigop .
Require Import signed reals ereal topology normedtype sequences real_interval.
Require Import esum measure lebesgue_measure numfun.
Require Import esum measure lebesgue_measure numfun exp itv.
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Maybe this is exp.v that should depend on lebesgue_integral.v (see the proof of convexity of powR).

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Not being able to decide whether to put it in exp.v, we introduce a new file hoelder.v for results that depend on lebesgue_integral.v and exp.v (it will soon welcome the convexity of powR and Minkowski's inequality).

@affeldt-aist affeldt-aist modified the milestones: 0.6.4, 0.6.5 Jul 28, 2023
@affeldt-aist affeldt-aist force-pushed the probability_20230603 branch 8 times, most recently from f9c53cf to f4ba8df Compare August 9, 2023 14:42
@affeldt-aist affeldt-aist force-pushed the probability_20230603 branch 2 times, most recently from e4eb08c to e327f7e Compare August 22, 2023 15:09
Copy link
Contributor

@zstone1 zstone1 left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Great. I'll mention here that the 0 case is invalid right now. I think it's just mu (f^-1 (setT \ {0})) but that can be easily added later without changing any lemma definitions.

But this looks good to me.

@affeldt-aist affeldt-aist merged commit f506383 into math-comp:master Sep 14, 2023
16 of 20 checks passed
affeldt-aist added a commit to affeldt-aist/analysis that referenced this pull request Sep 27, 2023
* tentative proof of Hoelder's inequality

* tentative def of ess sup

* fix case p = 0 of Lnorm

Co-authored-by: Alessandro Bruni <[email protected]>
proux01 pushed a commit that referenced this pull request Sep 28, 2023
* tentative proof of Hoelder's inequality

* tentative def of ess sup

* fix case p = 0 of Lnorm

Co-authored-by: Alessandro Bruni <[email protected]>
@proux01 proux01 removed the TODO: MC2 port This PR must be ported to mathcomp 2 now that the. Remove this label when the port is done. label Sep 28, 2023
IshiguroYoshihiro pushed a commit to IshiguroYoshihiro/analysis that referenced this pull request Oct 24, 2023
* tentative proof of Hoelder's inequality

* tentative def of ess sup

* fix case p = 0 of Lnorm

Co-authored-by: Alessandro Bruni <[email protected]>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
enhancement ✨ This issue/PR is about adding new features enhancing the library
Projects
None yet
Development

Successfully merging this pull request may close these issues.

6 participants