Timeline for Elementary $\mathrm{Ext}^1$ intuition
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
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| S Oct 8, 2020 at 20:15 | history | suggested | ArB | CC BY-SA 4.0 |
Typeset in Latex
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| Oct 8, 2020 at 19:10 | review | Suggested edits | |||
| S Oct 8, 2020 at 20:15 | |||||
| Aug 17, 2010 at 15:39 | comment | added | Robert Bruner | Or the two nontrivial extensions of $Z/3Z$ by $Z/3Z$. | |
| Oct 26, 2009 at 1:05 | comment | added | Graham Leuschke | Just as a minor clarification, Ext^1 doesn't classify the middle modules in the extension, but the whole extension itself. There are relatively easy examples of two extensions with the same three modules (in the same positions) that give different elements of Ext^1. I think the three modules in the easiest example are all smallish direct sums of Z/2Z and Z/4Z. | |
| Oct 25, 2009 at 23:50 | history | edited | Greg Muller | CC BY-SA 2.5 |
deleted 27 characters in body
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| Oct 25, 2009 at 23:42 | history | answered | Greg Muller | CC BY-SA 2.5 |