A note on the hyperreflexivity constant for certain reflexive algebras
Volume 134 / 1999
Studia Mathematica 134 (1999), 203-206 DOI: 10.4064/sm-134-3-203-206
Using results on the reflexive algebra with two invariant subspaces, we calculate the hyperreflexivity constant for this algebra when the Hilbert space is two-dimensional. Then by the continuity of the angle for two subspaces, there exists a non-CSL hyperreflexive algebra with hyperreflexivity constant C for every C>1. This result leads to a kind of continuity for the hyperreflexivity constant.