Timeline for Which linear combinations of simple roots are roots
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 21, 2022 at 14:56 | comment | added | Allen Knutson | I stole the file and stuck it under my web page where it should stay a good long time (link changed in my answer as well). | |
| Jun 21, 2022 at 14:55 | history | edited | Allen Knutson | CC BY-SA 4.0 |
fixed link
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| Jun 20, 2022 at 20:16 | comment | added | LSpice | Thanks! | |
| Jun 20, 2022 at 14:41 | comment | added | Allen Knutson | They're easily derived from the rank 2 cases. When you reflect at a long root, you replace its value by the sum of its neighbors', minus its value. When you reflect at a short root, then when summing over the neighbors you have to weight the long neighbors by 2 or 3. For example in the F_4 example a-b=>c-d, if you reflect the b it becomes a+c-b, but if you reflect the c it becomes 2b+d-c. | |
| Jun 16, 2022 at 17:25 | comment | added | LSpice | I think that these are the notes that now appear at math.toronto.edu/balazse/reflection_groups_2016.pdf . Elek simply says that the rules can be modified to handle the non-simply laced case; do you know how? | |
| Sep 24, 2019 at 20:41 | comment | added | Allen Knutson | I don't know that he wrote it anywhere (but I won't say he didn't); he told me about it in person at some point. | |
| Jul 17, 2019 at 17:53 | comment | added | LSpice | I assume it's named after Kostant since he discussed it somewhere; do you happen to have a reference? | |
| Jun 18, 2014 at 12:10 | vote | accept | Xin Nie | ||
| Jun 18, 2014 at 10:51 | vote | accept | Xin Nie | ||
| Jun 18, 2014 at 12:10 | |||||
| Jun 17, 2014 at 13:41 | history | answered | Allen Knutson | CC BY-SA 3.0 |