Аннотация:
The relation between natural classes and torsion free classes of modules is studied. The mapping $\phi\colon R$-nat $\to\boldsymbol{\EuScript P}$ between corresponding lattices is defined and some properties of $\phi$ are shown, in particular, the compatibility of $\phi$ with operations of unions in lattices.
Ключевые слова и фразы:Torsion, torsion free class, natural class, lattice of torsions, frame.