<i>A</i><sub>ϕ</sub>-Invariant Subspaces on the Torus
<i>A</i><sub>ϕ</sub>-Invariant Subspaces on the Torus
Abstract Generalizing the notion of invariant subspaces on the 2-dimensional torus T 2 , we study the structure of A ϕ-invariant subspaces of L 2 ( T 2 ). A complete description is given of A ϕ -invariant subspaces that satisfy conditions similar to those studied by Mandrekar, Nakazi, and …