Lie Semialgebras in reductive Lie algebras

This paper gives some basic facts on Lie semialgebras and shows the crucial steps that lead to a classification of semialgebras in a class of Lie algebras that contains the reductive ones. The classification of invariant wedges by Hilgert and Hofmann is a prerequisite. This paper was presented at the Conference on “The analytical and topological theory of semigroups” in Oberwolfach, January 29 through February 4, 1989