A conjecture of Gromov states that a one-ended word-hyperbolic group must contain a subgroup that is isomorphic to the fundamental group of a closed hyperbolic surface. Recent papers by Gordon and Wilton and by Kim and Wilton give sufficient conditions for hyperbolic surface groups to be embedded in a hyperbolic Baumslag double G. Using Nielsen cancellation methods based on techniques from previous work by the second author, we prove that a hyperbolic orientable surface group of genus 2 is embedded in a hyperbolic Baumslag double if and only if the amalgamated word W is a commutator: that is, W = [U, V] for some elements U, V is an element of F. Furthermore, a hyperbolic Baumslag double G contains a non-orientable surface group of genus 4 if and only if W = X(2)Y(2) for some X, V is an element of F. G can contain no non-orientable surface group of smaller genus.
Proceedings of the Edinburgh Mathematical Society
Fine, Benjamin and Rosenberger, Gerhard, "Surface Groups Within Baumslag Doubles" (2011). Mathematics Faculty Publications. 11.
B. Fine, and G. Rosenberger. Surface Groups Within Baumslag Doubles, Proceedings of the Edinburgh Mathematical Society. 54 (Part I), 91-97.