{ "id": "1402.3886", "version": "v4", "published": "2014-02-17T04:06:21.000Z", "updated": "2015-05-27T02:19:28.000Z", "title": "Bounds for the Hilbert Transform with Matrix $A_2$ Weights", "authors": [ "Kelly Bickel", "Stefanie Petermichl", "Brett Wick" ], "comment": "13 pages. v3: Revised to address referee comments and include additional references. v4: Grant information added", "categories": [ "math.CA" ], "abstract": "Let $W$ denote a matrix $A_2$ weight. In this paper, we implement a scalar argument using the square function to deduce square-function type results for vector-valued functions in $L^2(\\mathbb{R},\\mathbb{C}^d)$. These results are then used to study the boundedness of the Hilbert transform and Haar multipliers on $L^2(\\mathbb{R},\\mathbb{C}^d)$. Our proof shortens the original argument by Treil and Volberg and improves the dependence on the $A_2$ characteristic. In particular, we prove that the Hilbert transform and Haar multipliers map $L^2(\\mathbb{R},W,\\mathbb{C}^d)$ to itself with dependence on on the $A_2$ characteristic at most $[W]_{A_2}^{\\frac{3}{2}} \\log [W]_{A_2}$.", "revisions": [ { "version": "v3", "updated": "2014-08-11T14:42:27.000Z", "comment": "13 pages. Revised to address referee comments and include additional references", "journal": null, "doi": null }, { "version": "v4", "updated": "2015-05-27T02:19:28.000Z" } ], "analyses": { "subjects": [ "42A50" ], "keywords": [ "hilbert transform", "deduce square-function type results", "haar multipliers map", "scalar argument", "square function" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1402.3886B" } } }