Timeline for Amenability of the pair $(GL(2,\mathbb{Q})^+,SL(2,\mathbb{Z}))$
Current License: CC BY-SA 3.0
4 events
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| Sep 24, 2013 at 7:48 | comment | added | user23860 | @YvesCornulier: I think the continuity of co-amenability is an immediate corollary of the fixed point property. So ignore my previous comment. BTW, I appreciate your help. | |
| Sep 24, 2013 at 7:14 | comment | added | YCor | The answer is negative: indeed otherwise by considering the dense homomorphism into $PGL_2(\mathbb{Q}_p)$, we would infer that $PGL_2(\mathbb{Z}_p)$ is co-amenable in the latter. Since it is compact, this would mean that $PGL_2(\mathbb{Q}_p)$ is amenable, a contradiction. | |
| Sep 24, 2013 at 7:12 | comment | added | YCor | This is usually called "$H$ is co-amenable in $G$". | |
| Sep 24, 2013 at 4:40 | history | asked | user23860 | CC BY-SA 3.0 |