Timeline for Proof that the inclusion $\Delta \to \mathbf{Pos}$ preserves colimits
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 27 at 3:53 | comment | added | Tim Campion | There’s also some yoga about most of the pushouts which exists in $\Delta$ being absolute — they are preserved by any function whatsoever. For one thing, the pushout of any epimorphism along any epimorphism exists and is absolute (i.e. $\Delta$ is an elegant Reedy category). For another, many of the pushouts of monomorphisms which exist are absolute — I believe this fact is used in Cisinski’s Homotopical Algebra book | |
| Mar 26 at 11:44 | vote | accept | Calin Tataru | ||
| Mar 26 at 2:34 | answer | added | David Gao | timeline score: 3 | |
| Mar 25 at 23:53 | comment | added | Calin Tataru | No, it doesn't have most colimits (e.g. no coproducts) but it does have some. Actually once you show that $\Delta \to \mathbf{Pos}$ preserves colimits, you get that a diagram in $\Delta$ has a colimit iff its colimit in $\mathbf{Pos}$ is totally ordered, so it's easy to check which diagrams in $\Delta$ have colimits. | |
| Mar 25 at 23:30 | comment | added | Andrej Bauer | $\Delta$ doesn't have too many colimits, does it? | |
| Mar 25 at 22:07 | review | Close votes | |||
| Apr 1 at 3:03 | |||||
| S Mar 25 at 21:39 | review | First questions | |||
| Mar 25 at 23:44 | |||||
| S Mar 25 at 21:39 | history | asked | Calin Tataru | CC BY-SA 4.0 |