Timeline for Non congruence subgroups containing congruence subgroups.
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 6, 2012 at 15:19 | comment | added | Marc Palm | Okay, I recognize them now as the other maximal compact subgroup, which are useful when classifying supercuspidals. | |
| Jan 27, 2012 at 10:58 | vote | accept | Marc Palm | ||
| Jan 27, 2012 at 10:50 | comment | added | François Brunault | This normalizer is indeed a discrete subgroup of $\mathrm{PSL}_2(\mathbf{R})$. For the property that no conjugate is contained in $\mathrm{PSL}_2(\mathbf{Z})$, I think one needs some assumption on $N$. This is true for example if $N$ is prime (this is Exercise 1.46 in Shimura's book Intro. to the arithm. theory of autom. functions). But in general I think there are counterexamples e.g. for $N=p^4$ with $p$ prime. | |
| Jan 27, 2012 at 10:26 | history | answered | David Loeffler | CC BY-SA 3.0 |