We give a detailed description of the structure of the actor 2-crossed module related to the automorphisms of a crossed module of groupoids. This generalises work of Brown and Gilbert for the case of crossed modules of groups, and part of this is needed for work on 2-dimensional holonomy to be developed elsewhere.
C1 Univ Coll N Wales, Sch Informat, Div Math, Bangor LL57 1UT, Gwynedd, Wales.
Univ Inonu, Fac Sci & Art, Dept Math, Malatya, Turkey.