Timeline for singly-generated monoids in mathematics
Current License: CC BY-SA 2.5
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 18, 2011 at 22:59 | vote | accept | James Propp | ||
| Feb 4, 2011 at 1:29 | comment | added | Harry Gindi | @Martin: There is an article on the nLab. Iterating the plus construction gives you a weakly equivalent object that descends effectively on "covers of higher depth". I tihnk it's on the page about Cech cohomology and also on hypercovers if you want to check it out. | |
| Feb 4, 2011 at 1:27 | comment | added | Harry Gindi | It's worth noting that the single-plus construction does not have an adjointness property (there is a different functor that is an adjoint to the inclusion $SepPsh\to Psh$, though). I'm only posting this comment (for posterity's sake) because I was confused for a while about why one would use it if it doesn't have a universal property, but this post explains why (namely that higher iterates ensure that higher cocycle conditions are met). +1. | |
| Feb 3, 2011 at 9:54 | comment | added | Martin Brandenburg | Very nice. Could you indicate why we have to do the plus construction three times when we work in the Cat-enriched setting? | |
| Feb 3, 2011 at 0:37 | history | answered | Steve Lack | CC BY-SA 2.5 |