Zulip Chat Archive

Stream: mathlib4

Topic: Why are limits in category noncomputable?


Kenny Lau (Jun 25 2025 at 14:04):

Was this to prevent diamonds?

Kevin Buzzard (Jun 25 2025 at 14:09):

Because you can't compute them in general?

Kenny Lau (Jun 25 2025 at 14:09):

well i can just form the product type (in the category Type)

Aaron Liu (Jun 25 2025 at 14:11):

That a specific example of a limit which is computable

Aaron Liu (Jun 25 2025 at 14:11):

that doesn't mean they're computable in general

Joël Riou (Jun 25 2025 at 14:14):

For binary products with good definitional properties, we have the API FiniteChosenProducts.

Adam Topaz (Jun 25 2025 at 14:28):

And in general you can work with an explicit (co)limit (co)cone if you want to have some special properties of the (co)limit.

Antoine Chambert-Loir (Jun 25 2025 at 22:02):

That won't give you an algorithm to decide whether two distinct objects are some level stay distinct in every subsequent level.


Last updated: Dec 20 2025 at 21:32 UTC