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Dualize limits, right Kan extensions, and monads #1442

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Merged
merged 23 commits into from
Jun 21, 2025

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ben-connors
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This explicitly dualizes limits, right Kan extensions, and monads. The definitions and proofs are exactly dual, save for certain parts of cocones where re-use of coherence-triangle-hom-Precategory meant a rotation was needed.

This also fixes a minor indendation problem in monads.

@ben-connors ben-connors marked this pull request as ready for review June 9, 2025 17:00
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ben-connors commented Jun 9, 2025

I've made your suggested changes for both left and right (Kan) extensions.

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I forgot that I also needed pushouts, so I dualized them from pullbacks as well. I made some changes to pullbacks since a couple of the names didn't match conventions; these weren't used anywhere else in the library.

I dualized pushouts using pullbacks in the opposite category: same as for coproducts/products dualizing the definition explicitly gives something judgementally equal to the concept in the opposite category, and this way there's only one definition/proof in the library.

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I removed the pushout and pullback business, they're in #1448.

@fredrik-bakke
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Sorry for being so slow to review this one. I'll try and finish my review today, so hang tight!

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Looks great!

ben-connors and others added 2 commits June 21, 2025 11:37
Co-authored-by: Fredrik Bakke <fredrbak@gmail.com>
@fredrik-bakke fredrik-bakke enabled auto-merge (squash) June 21, 2025 22:03
@fredrik-bakke fredrik-bakke merged commit 8a39e48 into UniMath:master Jun 21, 2025
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2 participants