Timeline for Does Ext commute with direct limit?
Current License: CC BY-SA 2.5
7 events
| when toggle format | what | by | license | comment | |
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| Feb 15, 2016 at 4:10 | answer | added | user87684 | timeline score: 5 | |
| May 27, 2010 at 21:33 | vote | accept | ashpool | ||
| May 27, 2010 at 6:29 | answer | added | Sasha | timeline score: 2 | |
| May 27, 2010 at 4:25 | answer | added | Torsten Ekedahl | timeline score: 8 | |
| May 27, 2010 at 4:11 | comment | added | Jack Schmidt | For injectives this is just Baer's criterion. The interesting notion where the test modules M are required to be finitely presented yields Q that are called FP-injective or absolutely pure. They are the pure submodules of injective modules, and over Prüfer domains they are the divisible modules. Ext definitely does not commute will-nilly with direct limits since Q is a direct limit of Zs, but Ext(Q,Z)=R is not equal to the limit of Ext(Z,Z)=0. | |
| May 27, 2010 at 3:42 | history | edited | ashpool | CC BY-SA 2.5 |
edited title; deleted 45 characters in body; edited title
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| May 27, 2010 at 2:23 | history | asked | ashpool | CC BY-SA 2.5 |