A note on constrained convergence Original Research Article

The entrywise convergence of the constrained powers PAnQ of matrices is investigated. A new proof of the characterization of convergence, obtained recently by R.E. Hartwig and P. imageemrl [Rocky Mt. J. Math. 29 (1) (1999) 177], is presented. As an important tool we use a theorem from the theory of Diophantine approximation.