Timeline for Why Weyl group associated to Cartan matrix which defines positive definite bilinear form is finite?
Current License: CC BY-SA 3.0
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| Oct 18, 2011 at 4:23 | comment | added | Theo Johnson-Freyd | "discrete" here means "is discrete with the induced topology from the ambient Lie group". If you think about the irrational angle, you'll see that what you've done is given a homomorphism from the discrete group $\mathbb Z$ into $\mathrm{SO}(2)$, but the image is not discrete as a topological space. | |
| Oct 18, 2011 at 3:41 | comment | added | Mariano Suárez-Álvarez | Your question is off-topic here, as explained in the FAQ. math.stackexchange.com is a good place, to ask, though. | |
| Oct 18, 2011 at 3:40 | comment | added | Mariano Suárez-Álvarez | That is not a counterexample, because the subgroup is not discrete. | |
| Oct 18, 2011 at 3:39 | history | asked | ka9q | CC BY-SA 3.0 |