of ZfiΓ-modules and ZH-homomorphisms will be called an augmentation sequence if A is a finitely generated Ziϊ-module. Since ZH is a noetherian ring, A is then a finitely presented Zff-module; also, the module B in an augmentation sequence is finitely presented, since it is isomorphic to a submodule of A. For instance, if L £ S is a tame link of m components, G = π^S — L), and G is the commutato...