Non-hyperreflexive reflexive spaces of operators
We study operators whose commutant is reflexive but not hyperreflexive. We construct a $C_0$ contraction and a Jordan block operator $S_B$ associated with a Blaschke product $B$ which have the above mentioned property. A sufficient condition for hyperreflexivity of $S_B$ is given. Some other results related to hyperreflexivity of spaces of operators that could be interesting in themselves are proved.