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Gluing for Free cat with terminal objects #95

Merged
merged 5 commits into from
Jun 4, 2024
Merged

Gluing for Free cat with terminal objects #95

merged 5 commits into from
Jun 4, 2024

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maxsnew
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@maxsnew maxsnew commented May 22, 2024

I got started on implementing some metatheory for free categories with terminal objects. I got up to constructing the eliminator that constructs a local section but see we actually don't have the proof that VerticalTerminal is preserved by reindexing or that it implies LiftedTerminal. @hejohns please add those to this PR

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hejohns commented May 22, 2024

gah I guess I forgot to graft those over

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hejohns commented May 22, 2024

Not these?

Verticalᴰ/𝟙→LiftedTermᴰ : Verticalᴰ/𝟙 LiftedTerminalᴰ Cᴰ term

reind-VerticalTerminalsᴰ : VerticalTerminalsᴰ (reindex Dᴰ F)

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maxsnew commented May 22, 2024

Well they don't have anything to do with fibrations so why would I look there

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hejohns commented May 22, 2024

I can move these, but I had them under Fibration/ for uniformity.
Or at least Vertical→Lifted in general should be under Fibration/.
I agree (not that you're necessarily saying this) that preservation under reindexing should get moved to Displayed/Limit/Terminal

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maxsnew commented May 22, 2024 via email

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maxsnew commented May 22, 2024 via email

@maxsnew maxsnew marked this pull request as ready for review May 29, 2024 19:56
@maxsnew maxsnew force-pushed the terminal-gluing branch from 89d6b5e to 72ed2ec Compare May 29, 2024 19:59
@maxsnew maxsnew force-pushed the terminal-gluing branch from 72ed2ec to fb4f110 Compare May 29, 2024 20:30
@maxsnew maxsnew requested a review from hejohns May 29, 2024 20:36
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Looks good to merge.
I think I follow how we want to do these gluing examples.

I don't get at the moment why the uniqueness of normal forms has a path issue while the uniqueness of canonical forms is just fine, but maybe I'll get some idea after doing canonical forms for free cartesian categories.

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maxsnew commented Jun 4, 2024

I don't get at the moment why the uniqueness of normal forms has a path issue while the uniqueness of canonical forms is just fine, but maybe I'll get some idea after doing canonical forms for free cartesian categories.

I think it's just cubical nonsense because the NFs are a more complicated data type than sums. It could be a bug in cubical Agda for all we know

@maxsnew maxsnew merged commit 7dcffbe into main Jun 4, 2024
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@maxsnew maxsnew deleted the terminal-gluing branch June 4, 2024 14:08
@hejohns hejohns mentioned this pull request Jun 27, 2024
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2 participants