Timeline for Existence of a Sub-Category of the Category of Topological Spaces
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 18, 2013 at 0:49 | comment | added | Andrej Bauer | It was not meant to be a very serious comment :-) | |
| Mar 17, 2013 at 21:35 | comment | added | David White | @Joaquin: In the language of topological spaces, the characterization I linked to above says: ``the subcategory $C_0$ contains only countably many objects up to isomorphism, generates $Top$ under inverse limits, for any $A,B\in C_0$ there is a $C\in C_0$ they both embed in, and if $A\in C_0$ embeds in both $B$ and $C$ in $C_0$ then there's some $D\in C_0$ that $B$ and $D$ embed in such that this square commutes.'' Perhaps it would be a good exercise to check that Andrej's examples satisfy this property. It's easy to check for $C_0=$ Graph or Discrete | |
| Mar 17, 2013 at 21:01 | comment | added | Andrej Bauer | You were a bit too hasty in accepting answers... | |
| Mar 17, 2013 at 20:57 | vote | accept | Joaquín Moraga | ||
| Mar 17, 2013 at 23:40 | |||||
| Mar 17, 2013 at 19:56 | comment | added | Joaquín Moraga | Well, we have two examples now, the subcategory of Graphs and the subcategory of all discrete spaces of at most a given cardinality. Maybe the second Question can be answered now. If noone post a more acurrate answer i will accept yours as correct. Thanks. | |
| Mar 17, 2013 at 19:48 | history | answered | David White | CC BY-SA 3.0 |