Involution and commutator length for complex hyperbolic isometries
  We study decompositions of complex hyperbolic isometries as products of involutions. We show that PU(2,1) has involution length 4 and commutator length 1, and that for all $n \geqslant 3$ PU($n$,1) has involution length at most 8. 
Julien Paupert and Pierre Will
math.GT