If G is a free product of finite groups, let ΣAut1(G) denote all (necessarily symmetric) automorphisms of G that do not permute factors in the free product. We show that a McCullough–Miller and Gutiérrez–Krstić derived (also see Bogley–Krstić) space of pointed trees is an EΣAut1(G)-space for these groups.
International Journal of Algebra and Computation
Chen, Yuqing; Glover, Henry H.; Jensen, Craig A. Proper actions of automorphism groups of free products of finite groups. Internat. J. Algebra Comput. 15 (2005), no. 2, 255–272.