ABSTRACT
This chapter considers the deformations of finite or infinite dimensional Lie algebras over a field of characteristic 0. The deformation theory of Lie algebras is studied much less. There is confusion – and errors – in the literature when one tries to describe all the nonequivalent deformations of a given Lie algebra. For a proper procedure, one needs an appropriate theory of Massey operations and use Harrison cohomology. The chapter outlines a construction which gives a method to compute a versai deformation of a given Lie algebra by describing the base of this deformation. It also highlights the obstructions to extending deformations.
