{ "id": "2303.17994", "version": "v1", "published": "2023-03-31T12:11:21.000Z", "updated": "2023-03-31T12:11:21.000Z", "title": "Helson-Lowdenslager and de Branges type theorems in the setting of continuous rotationally symmetric norms", "authors": [ "Apoorva Singh", "Niteesh Sahni" ], "categories": [ "math.FA" ], "abstract": "A Helson-Lowdenslager type result has been proved by Chen in the context of Lebesgue spaces of the unit circle equipped with a continuous rotationally symmetric norm by studying the simply invariant subspaces of the operator of multiplication by the coordinate function $z$. In this paper, we generalize Chen's result by obtaining a description of simply invariant subspaces for multiplication by $z^n$. A de Branges type result is also proved for Hardy spaces equipped with continuous rotationally symmetric norms.", "revisions": [ { "version": "v1", "updated": "2023-03-31T12:11:21.000Z" } ], "analyses": { "subjects": [ "47A15", "30H10", "47B38" ], "keywords": [ "continuous rotationally symmetric norm", "branges type theorems", "simply invariant subspaces", "branges type result", "helson-lowdenslager type result" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }