on
http://www.win.tue.nl/~aeb/graphs/Brouwer-Haemers.html, I see that the automorphism group of a certain graph is described as
.2))
.
I understand this group is a composition of

,but exactly what does the . and : represent? Is it semidirect product, wreath product, or something else? I've been unable to find more informations on this notation elsewhere..