The inaccessible invariant subspaces of certain $C\sb{0}$\ operators

John Daughtry
1980 Proceedings of the American Mathematical Society  
We extend the Douglas-Pearcy characterization of the inaccessible invariant subspaces of an operator on a finite-dimensional Hubert space to the cases of algebraic operators and certain C0 operators on any Hubert space. This characterization shows that the inaccessible invariant subspaces for such an operator form a lattice. In contrast to D. Herrero's recent result on hyperinvariant subspaces, we show that quasisimilar operators in the classes under consideration have isomorphic lattices of inaccessible invariant subspaces.
doi:10.1090/s0002-9939-1980-0548083-x fatcat:45x2fgpsyjhzbiqopuxubapocy