The Balance of Tor.
We prove that if is an abelian -group with a nice subgroup so that is a -group, then is a -group if and only if is a -subgroup in provided that is equipped with a valuation induced by the restricted height function on . In particular, if in addition is pure in , is a -group precisely when is a -group. This extends the classical Dieudonné criterion (Portugal. Math., 1952) as well as it supplies our recent results in (Arch. Math. Brno, 2005), (Bull. Math. Soc. Sc. Math....