Invariance Preserving Conjugations on the Hardy Space

Abstract

We obtain a complete characterization of the class of conjugation operators $C$ on $H^2$ that map shift-invariant subspaces to shift-invariant subspaces. Alongside, we also obtain the existence and non-existence of conjugations that send shift-invariant subspaces to coinvariant subspaces.

arXiv comment10 pages, comments are welcome