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anonymous dude
Lv 5
Does SL(2,Z) contain a free group?
SL(2,R) contains F_2, but it doesn't seem possible to find generators with integer entries. Anyone know?
1 Answer
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- JBLv 71 decade agoFavorite Answer
The subgroup generated by
[1 2]
[0 1]
and
[1 0]
[2 1]
is free of rank 2.
See link below.
Source(s): http://en.wikipedia.org/wiki/Ping-pong_lemma
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