Subnormal subgroups of 3-dimensional Poincaré duality groups
We show that if a 3-dimensional Poincaré duality group G has a nontrivial almost finitely presentable subnormal subgroup of infinite index then either G is virtually the group of a surface bundle over the circle or the subgroup is infinite cyclic and normal in G.
almost finitely presentable subnormal subgroup of infinite index
group of a surface bundle over the circle
scientific article; zbMATH DE number 4138780