ON CLOSED SUBGROUPS OF THE ISOMETRY GROUP OF THREE DIMENSIONAL MINKOWSKI SPACE

In this paper we study the closed Lie subgroups of the isometry group of three dimensional Minkowski space R1;2. Among other results, we prove that if the linear part of G has some unipotent element, then the action of G on R1;2 is not proper. we determine the representation of the Lie group G in some different cases as well.