NORM-PRINCIPAL BIMODULES OF NEST ALGEBRAS

Let H be a separable Hibert space,N be a complete nest of closed subspaces of H and be the set of compact operators in (H). We denote that E=∨{N∈: dim N<+∞} and that E,=∨{N~⊥: N∈ and dim(N~⊥)<+∞}. A nest has order type Ⅰ if is an infinite set and satisfies one of the following conditions(1)and (2): (1)dim E<+∞