Timeline for What are your favorite concrete examples of limits or colimits that you would compute during lunch?
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
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| Jan 21, 2014 at 15:02 | comment | added | Ronnie Brown | @Todd: I mention that the groupoid example of the integers was in essence in my 1967 paper on van Kampen's theorem and was in the 1968 book on Topology. | |
| Jan 20, 2014 at 18:00 | comment | added | Ronnie Brown | @Todd: That example is a good one, and can also be phrased as a pushout in the category $Cat$ of small categories, noting that $Cat \to Sets$ is a bifibration of categories. Thanks also for the references. | |
| Jan 18, 2014 at 21:53 | comment | added | Todd Trimble | I was thinking about this example too, except mine was the coequalizer in $\mathbf{Cat}$ of the two object inclusions of the terminal category $\mathbf{1}$ into the arrow category $\mathbf{2}$. The coequalizer is the monoid of natural numbers made into a 1-object category. This example appears in Lawvere's Category of Categories paper, and in Mathematics Made Difficult. | |
| S Jan 18, 2014 at 15:32 | history | answered | Ronnie Brown | CC BY-SA 3.0 | |
| S Jan 18, 2014 at 15:32 | history | made wiki | Post Made Community Wiki by Ronnie Brown |