Varieties of Two-Step Solvable Algebras of Type (1, 1)

The structure of the set of all non-nilpotent subvarieties of the variety of two-step solvable algebras of type (1,1) is studied. An additive basis of a free metabelian (1,1)-algebra is constructed. It is proved that any identity in a non-nilpotent metabelian (1,1)-algebra of degree ≥6 is a consequence of four defining relations.