Let K(R) denote the set of the
kernel functors of the ring R and let ∞ be the trivial kernel functor defined by
setting ∞(M) = M for every right module M. The absolutely torsion-free
rings, that is, the rings R for which σ(R) = 0 for all σ ∈ K(R),σ≠∞, have
been introduced by Rubin as a non commutative analogue of the integral
domains.
In this paper a categorical characterization (in terms of finitely generated
projective modules) of absolutely torsion-free rings is obtained. As a consequence, all
of Rubin’s results are proved in a different fashion and generalization of most
of them are provided. Additional properties of this class of rings are also
exhibited.
Finally, absolutely torsion-free rings with torsionless injective hull are also
considered.
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