We characterize all such algebras: if a matrix algebra A does not share invariant subspaces with its commutant, then it must be similar to an amplification of a full matrix algebra. Then, we show that ...

Reinhold Schneider, Thorsten Rohwedder, Alexey Neelov, Johannes Blauert, DIRECT MINIMIZATION FOR CALCULATING INVARIANT SUBSPACES IN DENSITY FUNCTIONAL COMPUTATIONS OF THE ELECTRONIC STRUCTURE, Journal ...