Timeline for Lattice of subcategories: subobject classifier in Cat
Current License: CC BY-SA 2.5
4 events
| when toggle format | what | by | license | comment | |
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| Jun 21, 2010 at 16:12 | history | edited | Finn Lawler | CC BY-SA 2.5 |
added 92 characters in body
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| Jun 21, 2010 at 16:09 | comment | added | Finn Lawler | Oh, OK. My mistake. But as Michael Warren points out, if Cat had a subobject classifier then it would be a topos and so locally cartesian closed, but it isn't so it doesn't. | |
| Jun 21, 2010 at 0:10 | comment | added | Mike Shulman | What I meant on that page is that the 2-category Cat has no subobject classifier which classifies its 2-categorical subobjects (probably meaning fully faithful functors) 2-categorically, i.e. in terms of hom-categories rather than homsets. I'm not sure if the 1-category Cat has a subobject classifier in the 1-categorical sense. | |
| Jun 20, 2010 at 19:47 | history | answered | Finn Lawler | CC BY-SA 2.5 |