An alternative description of the torsion subgroup of the free centre-by-nilpotent of class 2-by-abelian group of rank at least four in terms of generators

Let F be a non-cyclic free group of rank d. In 1997, using homological methods, A. M. Sager described the torsion subgroup of the free centre-by-nilpotent of class (p-1)-by-abelian group F/[γp(F'),F] of rank d>=4 in terms of generators, where p is a prime number. In this thesis, using homological methods, we obtain an alternative description of this torsion subgroup in terms of generators in the special case p=3.