Timeline for Comultiplication on objects in an (abelian?) category
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
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| Oct 5, 2019 at 4:19 | comment | added | Qiaochu Yuan | @Adi: the "most universal" construction I can think of is just the diagonal map $C \ni c \mapsto (c, c) \in C \times C$, which exists for any category. In any category with finite products (which here is $\text{Cat}$ itself) this is the unique comonoid structure on any object wrt the product. | |
| Oct 4, 2019 at 17:47 | comment | added | Adi Ostrov | This seems a way less "canonical" or "natural" structure compared to direct sum and tensor product. It sure is interesting but it isn't what I had in mind. Is there some way to define a coproduct with, say, a universal property? | |
| Oct 1, 2019 at 20:20 | vote | accept | Adi Ostrov | ||
| Oct 1, 2019 at 20:10 | history | answered | Qiaochu Yuan | CC BY-SA 4.0 |