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[Merged by Bors] - feat(topology/vector_bundle): define some useful linear maps globally #14484

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@fpvandoorn fpvandoorn commented May 31, 2022

  • Define pretrivialization.symmₗ, pretrivialization.linear_map_at, trivialization.symmL, trivialization.continuous_linear_map_at
  • These are globally-defined (continuous) linear maps. They are linear equivalences on e.base_set, but it is useful to define these globally. They are defined as 0 outside e.base_set
  • These are convenient to define the vector bundle of continuous linear maps.

This (slightly) conflicts with #14462. Please merge that PR first, unless this reviews much more easily (branch vb-hom-floris has the merge conflict resolved)

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@fpvandoorn fpvandoorn added awaiting-review The author would like community review of the PR awaiting-CI The author would like to see what CI has to say before doing more work. labels May 31, 2022
@fpvandoorn fpvandoorn changed the title stuff from vb-hom feat(topology/vector_bundle): define some useful linear maps globally May 31, 2022
@github-actions github-actions bot removed the awaiting-CI The author would like to see what CI has to say before doing more work. label May 31, 2022
@fpvandoorn fpvandoorn added the blocked-by-other-PR This PR depends on another PR which is still in the queue. A bot manages this label via PR comment. label Jun 1, 2022
@mathlib-dependent-issues-bot mathlib-dependent-issues-bot removed the blocked-by-other-PR This PR depends on another PR which is still in the queue. A bot manages this label via PR comment. label Jun 1, 2022
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Comment on lines 529 to 584
{ cont := by { dsimp, rw [e.coe_linear_map_at b],
refine continuous_if_const _ (λ hb, _) (λ _, continuous_zero),
refine continuous_snd.comp (e.to_local_homeomorph.continuous_on.comp_continuous
(total_space_mk_inducing R F E b).continuous (λ x, e.mem_source.mpr hb)) },
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IMHO, this deserves a begin ... end block.

Also, can you explain why you mention (only propositionally equal) in the docstring? At least, I hope that the to_fun fields are defeq?

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No, they are not defeq because the one that is defined everywhere features an if then else. It is defined as if hb : b ∈ e.base_set then e.linear_equiv_at b hb else 0 so it's not defeq to e.linear_equiv_at b hb, it is only propeq to it when `b ∈ e.base_set.

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The real question is whether we really want to keep linear_equiv_at which isn't used anywhere else. Let's keep it for now and remember to delete it if we manage to go as far as jet bundles without ever using it.

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I rebased on master to solve conflicts.

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bors merge

@github-actions github-actions bot added ready-to-merge All that is left is for bors to build and merge this PR. (Remember you need to say `bors r+`.) and removed awaiting-review The author would like community review of the PR labels Jun 2, 2022
bors bot pushed a commit that referenced this pull request Jun 2, 2022
…#14484)

* Define `pretrivialization.symmₗ`, `pretrivialization.linear_map_at`, `trivialization.symmL`, `trivialization.continuous_linear_map_at`
* These are globally-defined (continuous) linear maps. They are linear equivalences on `e.base_set`, but it is useful to define these globally. They are defined as `0` outside `e.base_set`
* These are convenient to define the vector bundle of continuous linear maps.



Co-authored-by: Patrick Massot <patrickmassot@free.fr>
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bors bot commented Jun 2, 2022

Pull request successfully merged into master.

Build succeeded:

@bors bors bot changed the title feat(topology/vector_bundle): define some useful linear maps globally [Merged by Bors] - feat(topology/vector_bundle): define some useful linear maps globally Jun 2, 2022
@bors bors bot closed this Jun 2, 2022
@bors bors bot deleted the vb-symmL branch June 2, 2022 17:31
tomaz1502 pushed a commit that referenced this pull request Jun 3, 2022
…#14484)

* Define `pretrivialization.symmₗ`, `pretrivialization.linear_map_at`, `trivialization.symmL`, `trivialization.continuous_linear_map_at`
* These are globally-defined (continuous) linear maps. They are linear equivalences on `e.base_set`, but it is useful to define these globally. They are defined as `0` outside `e.base_set`
* These are convenient to define the vector bundle of continuous linear maps.



Co-authored-by: Patrick Massot <patrickmassot@free.fr>
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