Timeline for Why need the morphisms to form a set ?
Current License: CC BY-SA 2.5
6 events
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Dec 10, 2010 at 1:31 | comment | added | David Roberts♦ | To quote from Clark Barwick's arXiv paper math/1012.1889 out today, "We use the Universe Axiom of [SGA4 I, Exp I, §0], and we fix two universes U ∈ V. All rings, modules, schemes, etc., will be U-small. We employ the following notational conventions for categories or ∞-categories: (N.1) Roman characters A, B, C, . . . , etc., will denote categories and ∞-categories that are essentially V-small and locally U-small. (N.2) Bold characters A, B, C, . . . , etc., will denote categories and ∞-categories that are locally V-small." | |
Dec 9, 2010 at 22:26 | history | edited | David Roberts♦ | CC BY-SA 2.5 |
Added example
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Dec 9, 2010 at 21:46 | comment | added | BCnrd | Kevin, whenever we form Ext-sheaves, those Hom's had better be sets or else it is really confusing what is going on. | |
Dec 9, 2010 at 20:59 | history | edited | David Roberts♦ | CC BY-SA 2.5 |
added 17 characters in body
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Dec 9, 2010 at 20:53 | comment | added | Kevin Buzzard | This is great---thanks. I think this answer more than justifies the existence of the question. | |
Dec 9, 2010 at 20:40 | history | answered | David Roberts♦ | CC BY-SA 2.5 |