A set Ω of n × n matrices is
said to have Property T if the following two conditions are satisfied: (i) If Ω is looked
upon as a set of linear transformations of a vector space V of dimension n then V
has an Ω-decomposition into primary components; i.e. V = V1⊕⋯⊕ Vt,
where the restrictions of the elements of Ω to any Vi are primary linear
transformations; and (ii) V has an Ω-composition series with 1-dimensional
composition-factors.
Our aim in this paper will be to characterize sets of nonsingular linear
transformations having Property T.