The calculation of an invariant for Tor

Some isomorphisms of abelian groups involving the Tor functor

“…By Proposition 1.4, A must be reduced. By [16,Corollary 3.6], an S-group of the form Tox(A, G) = A must be totally projective, and by [6,Corollary 4], a totally projective group of this form must be a disc.…”