Nielsen realization for sphere twists of 3-manifolds
with L. Chen
Israel J. Math., to appear
For a 3-manifold M, the twist group Twist(M) is the subgroup of the mapping class group Mod(M) generated by twists about embedded 2-spheres. We study the Nielsen realization problem for subgroups of Twist(M). We prove that a group G<Twist(M) is realized by diffeomorphisms if and only if G is cyclic and M is a connected sum of lens spaces.