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@mans0954 mans0954 commented Sep 22, 2024

Defines the absolutely convex (or disked) hull of a subset of a locally convex space and proves a number of standard properties, including:

  • (subject to suitable conditions) the absolutely convex hull equals the convex hull of the balanced hull.
  • In a real vector space the absolutely convex hull of s equals the convex hull of s ∪ -s

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@mans0954 mans0954 added the t-analysis Analysis (normed *, calculus) label Sep 22, 2024
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github-actions bot commented Sep 22, 2024

PR summary 8d559b438f

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference

Declarations diff

+ AbsConvex
+ AbsConvex.absConvexHull_eq
+ AbsConvex.absConvexHull_subset_iff
+ AbsConvex.empty
+ AbsConvex.iInter
+ AbsConvex.inter
+ AbsConvex.sInter
+ AbsConvex.univ
+ Balanced.sInter
+ _
+ absConvexHull
+ absConvexHull_add_subset
+ absConvexHull_empty
+ absConvexHull_eq_convexHull_balancedHull
+ absConvexHull_eq_empty
+ absConvexHull_eq_iInter
+ absConvexHull_eq_self
+ absConvexHull_min
+ absConvexHull_mono
+ absConvexHull_nonempty
+ absConvexHull_univ
+ absConvex_absConvexHull
+ balancedHull_add_subset
+ balancedHull_convexHull_subseteq_absConvexHull
+ balancedHull_mono
+ balancedHull_subset_convexHull_union_neg
+ balanced_absConvexHull
+ convexHull_union_neg_eq_absConvexHull
+ convex_absConvexHull
+ mem_absConvexHull_iff
+ nhds_hasBasis_absConvex
+ nhds_hasBasis_absConvex_open
+ subset_absConvexHull
+ ⟨_,
- nhds_basis_abs_convex
- nhds_basis_abs_convex_open

You can run this locally as follows
## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.


variable {𝕜}

theorem absConvex_empty : AbsConvex 𝕜 (∅ : Set E) := ⟨balanced_empty, convex_empty⟩
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Suggested change
theorem absConvex_empty : AbsConvex 𝕜 (∅ : Set E) := ⟨balanced_empty, convex_empty⟩
theorem AbsConvex.empty : AbsConvex 𝕜 (∅ : Set E) := ⟨balanced_empty, convex_empty⟩

for dot notation. Same below. Feel free to open PRs to align the Balanced and Convex API to that new convention, btw

@YaelDillies YaelDillies added the awaiting-author A reviewer has asked the author a question or requested changes. label Sep 28, 2024
@YaelDillies YaelDillies changed the title feature(Analysis/LocallyConvex/AbsConvex): Define the Absolutely Convex Hull feat(Analysis/LocallyConvex/AbsConvex): Define the Absolutely Convex Hull Sep 28, 2024
mans0954 and others added 14 commits September 28, 2024 12:27
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
fbarroero pushed a commit that referenced this pull request Oct 2, 2024
…ointwise operations (#17253)

Provides `sInter` and `sUnion` versions of  pointwise algebraic operations on sets.

Needed in #17029



Co-authored-by: Christopher Hoskin <mans0954@users.noreply.github.com>
@mans0954 mans0954 removed the awaiting-author A reviewer has asked the author a question or requested changes. label Oct 5, 2024
@YaelDillies YaelDillies added the awaiting-author A reviewer has asked the author a question or requested changes. label Oct 11, 2024
mans0954 and others added 3 commits October 11, 2024 09:14
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
@mans0954 mans0954 removed the awaiting-author A reviewer has asked the author a question or requested changes. label Oct 11, 2024
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Thanks!

maintainer merge

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🚀 Pull request has been placed on the maintainer queue by YaelDillies.

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Thanks 🎉

bors merge

@leanprover-community-mathlib4-bot leanprover-community-mathlib4-bot added the ready-to-merge This PR has been sent to bors. label Oct 17, 2024
mathlib-bors bot pushed a commit that referenced this pull request Oct 17, 2024
…Hull (#17029)

Defines the absolutely convex (or disked) hull of a subset of a locally convex space and proves a number of standard properties, including:

-  (subject to suitable conditions) the absolutely convex hull equals the convex hull of the balanced hull.
- In a real vector space the absolutely convex hull of `s` equals the convex hull of `s ∪ -s`



Co-authored-by: Christopher Hoskin <mans0954@users.noreply.github.com>
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mathlib-bors bot commented Oct 17, 2024

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat(Analysis/LocallyConvex/AbsConvex): Define the Absolutely Convex Hull [Merged by Bors] - feat(Analysis/LocallyConvex/AbsConvex): Define the Absolutely Convex Hull Oct 17, 2024
@mathlib-bors mathlib-bors bot closed this Oct 17, 2024
@mathlib-bors mathlib-bors bot deleted the mans0954/absconvexhull branch October 17, 2024 07:52
mathlib-bors bot pushed a commit that referenced this pull request Oct 14, 2025
… a single ring of scalars (#29342)

Currently the definition of Absolutely Convex in Mathlib is a little unexpected:
```
def AbsConvex (s : Set E) : Prop := Balanced 𝕜 s ∧ Convex ℝ s
```
At the time this definition was formulated, Mathlib's definition of `Convex` required the scalars to be an `OrderedSemiring` whereas the definition of `Balanced` required the scalars to be a `SeminormedRing`. Mathlib didn't  have a concept of a semi-normed ordered ring, so a set was defined as `AbsConvex` if it is balanced over a `SeminormedRing` `𝕜` and convex over `ℝ`.

Recently the requirements for the definition of `Convex` have been relaxed (#24392, #20595) so it is now possible to use a single scalar ring in common with the literature.

Previous discussion:

- #17029 (comment)
- #26345 (comment)
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6 participants