Are you familiar with the category of complete atomic boolean algebras?
Through stone duality. What about them in particular?
Trivially, a co-X in C^op is the same but flipped as an X in C.
Then as you know, Stone duality says that CABA = Set^op.
So a co-X in CABA is the same but flipped as an X in Set.
(I think it works constructively too if one replaces Boolean with Heyting?)
Are you familiar with the category of complete atomic boolean algebras?
Through stone duality. What about them in particular?
Trivially, a co-X in C^op is the same but flipped as an X in C.
Then as you know, Stone duality says that CABA = Set^op.
So a co-X in CABA is the same but flipped as an X in Set.
(I think it works constructively too if one replaces Boolean with Heyting?)