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feat(MeasureTheory.VectorMeasure): variation defined as a supremum is equal to variation defined using the Hahn-Jordan decomposition#26168

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feat(MeasureTheory.VectorMeasure): variation defined as a supremum is equal to variation defined using the Hahn-Jordan decomposition#26168
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@oliver-butterley oliver-butterley commented Jun 19, 2025

Add signedMeasure_totalVariation_eq: if μ is a SignedMeasure then variation defined as a supremum is equal to variation defined using the Hahn-Jordan decomposition.

Co-authored-by: @yoh-tanimoto


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@mathlib4-merge-conflict-bot mathlib4-merge-conflict-bot added the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Nov 19, 2025
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This pull request has conflicts, please merge master and resolve them.

@grunweg grunweg changed the title feat(MeasureTheory.VectorMeasure) : variation defined as a supremum is equal to variation defined using the Hahn-Jordan decomposition. feat(MeasureTheory.VectorMeasure): variation defined as a supremum is equal to variation defined using the Hahn-Jordan decomposition Nov 19, 2025
@github-actions github-actions bot removed the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Jan 9, 2026
mathlib-bors bot pushed a commit that referenced this pull request Feb 10, 2026
…n for VectorMeasure (#26156)

This PR adds variation for any `VectorMeasure` using a supremum definition. Currently mathlib has `TotalVariation` defined for a signed measure using the Hahn-Jordan decomposition, but this doesn't generalise.

Motivation: generally this is an important concept but specifically as a step for proving RMK in the complex case which in turn is a step to prove the spectral theorem.


This PR was migrated from #25442. PR divided into smaller pieces, this is just the definition without additional lemmas. PRs adding further results related to variation are:
* #26160
* #26165 
* #26168 (shows that for `SignedMeasures` the two definitions of variation coincide)

Co-authored-by: @yoh-tanimoto
Co-authored-by: Yoh Tanimoto <[email protected]>
Co-authored-by: Yoh Tanimoto <[email protected]>
@mathlib-merge-conflicts mathlib-merge-conflicts bot added the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Feb 10, 2026
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This pull request has conflicts, please merge master and resolve them.

rao107 pushed a commit to rao107/mathlib4 that referenced this pull request Feb 18, 2026
…n for VectorMeasure (leanprover-community#26156)

This PR adds variation for any `VectorMeasure` using a supremum definition. Currently mathlib has `TotalVariation` defined for a signed measure using the Hahn-Jordan decomposition, but this doesn't generalise.

Motivation: generally this is an important concept but specifically as a step for proving RMK in the complex case which in turn is a step to prove the spectral theorem.


This PR was migrated from leanprover-community#25442. PR divided into smaller pieces, this is just the definition without additional lemmas. PRs adding further results related to variation are:
* leanprover-community#26160
* leanprover-community#26165 
* leanprover-community#26168 (shows that for `SignedMeasures` the two definitions of variation coincide)

Co-authored-by: @yoh-tanimoto
Co-authored-by: Yoh Tanimoto <[email protected]>
Co-authored-by: Yoh Tanimoto <[email protected]>
Maldooor pushed a commit to Maldooor/mathlib4 that referenced this pull request Feb 25, 2026
…n for VectorMeasure (leanprover-community#26156)

This PR adds variation for any `VectorMeasure` using a supremum definition. Currently mathlib has `TotalVariation` defined for a signed measure using the Hahn-Jordan decomposition, but this doesn't generalise.

Motivation: generally this is an important concept but specifically as a step for proving RMK in the complex case which in turn is a step to prove the spectral theorem.


This PR was migrated from leanprover-community#25442. PR divided into smaller pieces, this is just the definition without additional lemmas. PRs adding further results related to variation are:
* leanprover-community#26160
* leanprover-community#26165 
* leanprover-community#26168 (shows that for `SignedMeasures` the two definitions of variation coincide)

Co-authored-by: @yoh-tanimoto
Co-authored-by: Yoh Tanimoto <[email protected]>
Co-authored-by: Yoh Tanimoto <[email protected]>
pfaffelh pushed a commit to pfaffelh/mathlib4 that referenced this pull request Mar 2, 2026
…n for VectorMeasure (leanprover-community#26156)

This PR adds variation for any `VectorMeasure` using a supremum definition. Currently mathlib has `TotalVariation` defined for a signed measure using the Hahn-Jordan decomposition, but this doesn't generalise.

Motivation: generally this is an important concept but specifically as a step for proving RMK in the complex case which in turn is a step to prove the spectral theorem.


This PR was migrated from leanprover-community#25442. PR divided into smaller pieces, this is just the definition without additional lemmas. PRs adding further results related to variation are:
* leanprover-community#26160
* leanprover-community#26165 
* leanprover-community#26168 (shows that for `SignedMeasures` the two definitions of variation coincide)

Co-authored-by: @yoh-tanimoto
Co-authored-by: Yoh Tanimoto <[email protected]>
Co-authored-by: Yoh Tanimoto <[email protected]>
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