On a Beck-Putnam-Rehder Theorem
Mohammed Hichem Mortad · Bulletin of the Belgian Mathematical Society - Simon Stevin · 2010
We give a simple and easy proof of a result obtained by W. Rehder who generalized, in his turn, a famous result by Beck and Putnam.We then give a generalization to unbounded operators.* Supported in part by "Laboratoire de Mathématiques, Géométrie, Analyse, Contr ôle & Applications".