Timeline for Using the Yoneda embedding to talk about exactness in an additive category
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
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| S Nov 26, 2019 at 9:38 | history | suggested | Dat Minh Ha | CC BY-SA 4.0 |
Corrected LaTeX typo, specifically $[\mathcal{C},\mbox{Ab}]$.
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| Nov 26, 2019 at 7:50 | review | Suggested edits | |||
| S Nov 26, 2019 at 9:38 | |||||
| Jan 24, 2013 at 10:16 | comment | added | Jochen Wengenroth | In abelian categories exactness of the sequences involving Hom$(--,A)$ is measured by the derivatives of the Hom-functors which are traditionally called Ext. | |
| Jan 23, 2013 at 18:52 | answer | added | Martin Brandenburg | timeline score: 9 | |
| Jan 23, 2013 at 18:40 | comment | added | Qiaochu Yuan | You don't need kernels or images to talk about exactness. Exactness is equivalent to a certain square constructed from $A, B, C$ being both a pullback square and a pushout square, and constructing this square only requires the existence of a zero object. | |
| Jan 23, 2013 at 17:15 | history | asked | John Wiltshire-Gordon | CC BY-SA 3.0 |