ON SEMITRANSITIVE JORDAN ALGEBRAS OF MATRICES
Abstract
A set of linear operators on a vector space is said to be semitransitive if, given nonzero vectors x, y, there exists
such that either Ax = y or Ay = x. In this paper we consider semitransitive Jordan algebras of operators on a finite-dimensional vector space over an algebraically closed field of characteristic not two. Two of our main results are:
(1) Every irreducible semitransitive Jordan algebra is actually transitive.
(2) Every semitransitive Jordan algebra contains, up to simultaneous similarity, the upper triangular Toeplitz algebra, i.e. the unital (associative) algebra generated by a nilpotent operator of maximal index.