UC Davis

We prove a generalization of the classical Klein–Maskit combination theorem, in the free product case, in the setting of Anosov subgroups. Namely, if Γ A and Γ B are Anosov subgroups of a semisimple Lie group G of noncompact type, then under suitable topological assumptions, the group generated by Γ A and Γ B in G is again Anosov, and is naturally isomorphic to the free product Γ A∗ Γ B . Such a generalization was conjectured in Dey et al. (Math Z 293(1–2):551–578, 2019).