Hi,
I'm looking for examples of groups that are both Hopfian and Co-Hopfian. I have a non trivial (and beautiful, at least to me) example: $\mathrm{SL}(n,\mathbb{Z})$ (with $n>2$).


Do you know others (non trivial)?


Thank you.



Hopfian and Co-Hopfian groups (examples)
Mapping class groups of closed surfaces are both Hopfian and co-Hopfian (the former follows from residual finiteness, and the latter is due to Ivanov-McCarthy).


Out(F\_n) also has both properties (residual finiteness and a theorem of Farb-Handel).


