The classical deformation theory of Lie algebras involves different kinds of
Massey products of cohomology classes. Even the condition of extendibility of
an infinitesimal deformation to a formal one-parameter deformation of a Lie
algebra involves Massey powers of two dimensional cohomology classes which are
not powers in the usual definition of Massey products in the cohomology of a
differential graded Lie algebra. In the case of deformations with other local
bases, one deals with other, more specific Massey products. In the present work
a construction of generalized Massey products is given, depending on an
arbitrary graded commutative, associative algebra. In terms of these products,
the above condition of extendibility is generalized to deformations with
arbitrary local bases. Dually, a construction of generalized Massey products on
the cohomology of a differential graded commutative associative algebra depends
on a nilpotent graded Lie algebra. For example, the classical Massey products
correspond to the Lie algebra of strictly upper triangular matrices, while the
matric Massey products correspond to the Lie algebra of block strictly upper
triangular matrices.Comment: 13 pages, tex documen
