Timeline for Discrete subgroup of complex orthogonal group
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
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| Nov 21, 2014 at 3:40 | comment | added | Venkataramana | If $n\geq 5$, then all lattices are "arithmetic" and classification arises from Galois cohomology , Hasse principle, etc.You have to see the books of Margulis and of Platonov-Rapinchuk for details. If $n\leq 4$, then there are many more lattices. | |
| Nov 21, 2014 at 3:17 | comment | added | user42804 | What is the reference for some detailed discussion either lattice or only discrete subgroup? And what if n=4? | |
| Nov 21, 2014 at 3:11 | comment | added | Venkataramana | Do you want discrete subgroups with finite covolume or only discrete subgroups? In any case, there are many examples; if you want only discrete subgroups, a Schottky construction (ping-pong) gives you plenty. If you ask for lattices, many discrete groups can be constructed as unit groups of quadratic forms over an imaginary quadratic extension; a full classification is possible, if $n\geq 5$. | |
| Nov 21, 2014 at 1:58 | history | asked | user42804 | CC BY-SA 3.0 |