Contraction of lie superalge- bras and ambiguity of Dynkin diagrams

We study contractions of Lie superalgebras. Definition of flag contractions modified for work with superalgebras is proposed. We consider some features of flag contractions of Lie superalgebras, which are defined by different supermatrix structures. It is shown that these contractions are nonisomorphic. The Galilei superalgebras, arising after contractions of superalgebra of sl(2|1) are listed. Thenonadditivity and noncommutativity of the law of a velocity addition is shown.It is natural to consider these superalgebras as supergeneralization of the paraGalilean algebras described in [1]. Flag contractions of supergroups are defined by exponential map of flag contractions of superalgebras. Different actions of Galilean supergroup on flag superspaces are presented.