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[Merged by Bors] - feat(topology/algebra/order/compact): Sup is continuous #13347

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@fpvandoorn fpvandoorn commented Apr 11, 2022

  • Prove that the Sup of a binary function over a compact set is continuous in the second variable
  • Some other lemmas about Sup
  • Move and generalize is_compact.bdd_[above|below]_image
  • from the sphere eversion project

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@fpvandoorn fpvandoorn added the awaiting-review The author would like community review of the PR label Apr 11, 2022
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Other than a few minor comments this looks good to me.

Comment on lines +2191 to +2192
/-- A continuous function is bounded below on a compact set. -/
lemma is_compact.bdd_below_image {α : Type u} [topological_space α] [linear_order α]
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I understand why you put these here, but I think they might be better with the other things related to the extreme value theorem in topology.algebra.order.compact (for example, near is_compact.exists_forall_le). Although this is not a strong preference.

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I can take a look what will break if is_compact.bdd_[below|above] are moved to topology.algebra.order.compact

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In retrospect I think it's probably better to leave those lemmas where they are. They are related to the extreme value theorem, but much weaker, so I think it's fine to put them where they are.

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@fpvandoorn fpvandoorn added awaiting-author A reviewer has asked the author a question or requested changes and removed awaiting-review The author would like community review of the PR labels Apr 13, 2022
@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. and removed awaiting-author A reviewer has asked the author a question or requested changes labels Apr 13, 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 Apr 13, 2022
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bors d+

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bors bot commented Apr 14, 2022

✌️ fpvandoorn can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

@leanprover-community-bot-assistant leanprover-community-bot-assistant added delegated The PR author may merge after reviewing final suggestions. and removed awaiting-review The author would like community review of the PR labels Apr 14, 2022
Co-authored-by: Johan Commelin <johan@commelin.net>
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bors merge

@github-actions github-actions bot added the ready-to-merge All that is left is for bors to build and merge this PR. (Remember you need to say `bors r+`.) label Apr 14, 2022
bors bot pushed a commit that referenced this pull request Apr 14, 2022
* Prove that the `Sup` of a binary function over a compact set is continuous in the second variable
* Some other lemmas about `Sup`
* Move and generalize `is_compact.bdd_[above|below]_image`
* from the sphere eversion project
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bors bot commented Apr 14, 2022

Pull request successfully merged into master.

Build succeeded:

@bors bors bot changed the title feat(topology/algebra/order/compact): Sup is continuous [Merged by Bors] - feat(topology/algebra/order/compact): Sup is continuous Apr 14, 2022
@bors bors bot closed this Apr 14, 2022
@bors bors bot deleted the fpvandoorn/extreme branch April 14, 2022 14:09
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