On the indecomposability of Borel manifolds

Here we prove the indecomposability of the homogeneous space $G/T$ of a simple compact connected Lie group $G$ modulo a maximal torus $T$ (the author calls such manifolds Borel manifolds). From this and from the results of A. L. Onishchik we get a description of all the connected Lie groups which act transitively on Borel manifolds. This description is given in the paper.
Bibliography: 5 titles.