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Stream: community: general

Topic: a question on datatypes


view this post on Zulip Faré (Apr 10 2020 at 09:34):

If A is a datatype, what do -A, 1/A, 1/2 A mean, if anything?

view this post on Zulip James Wood (Apr 10 2020 at 09:38):

Faré said:

If A is a datatype, what do -A, 1/A, 1/2 A mean, if anything?

Not standardly, but there's some discussion of it here: https://groups.google.com/forum/#!topic/hott-cafe/jbPtbnnAczY

view this post on Zulip Faré (Apr 10 2020 at 09:40):

Maybe they kind of make sense in linear logic?
A-A cancels one choice for AA... maybe some weird operation to modify a program by invalidating a possible choice?
1/A1/A cancels AA in a product, so is like AA^\bot in linear logic, indicates that some function/continuation/operator/blah is consuming AA.

view this post on Zulip James Wood (Apr 10 2020 at 09:45):

Still then, I think it's quite difficult. You don't have IAAI ⊸ A ⊗ A^⊥, and you'd probably be missing a similar law for the additive negation.

view this post on Zulip James Wood (Apr 10 2020 at 09:46):

(Instead, you have IAAI ⊸ A ⅋ A^⊥.)

view this post on Zulip James Wood (Apr 10 2020 at 09:47):

I think I've thought about things like this before, and ended up with tensor and par collapsing. Maybe that'd be acceptable for what you're wanting, but it wasn't for me.

view this post on Zulip Bob Atkey (Apr 10 2020 at 09:49):

Tensor and Par collapsing essentially gets you a compact closed category, which one can think of as the categorification of abelian groups.

view this post on Zulip James Wood (Apr 10 2020 at 09:51):

Oh, that's a good point!

view this post on Zulip vikraman (Apr 10 2020 at 15:09):

Some of these can be made sense of in the context of reversible programming languages, some papers are listed here: https://amr-sabry.luddy.indiana.edu/research/ and a recent draft here: https://arxiv.org/abs/2002.07020

view this post on Zulip Sam Tenka (Apr 10 2020 at 15:59):

Also see Blass's "7 trees in 1"