{ "id": "1404.4380", "version": "v2", "published": "2014-04-16T20:27:59.000Z", "updated": "2015-09-28T16:33:57.000Z", "title": "Fourier multipliers for weighted $L^{2}$ spaces with Lévy-Khinchin-Schoenberg weights", "authors": [ "Nikolai K. Nikolski", "Igor E. Verbitsky" ], "comment": "Version 2: Remark at the end of Sec. 2 deleted, discussion of the splitting case added (Remarks after Lemma 2.1, Lemma 2.3, Lemma 3.8), Theorem 3.4 modified in the case $1/w \\not\\in L^1(\\mathbb{T})$, Secs. 4-5 unchanged", "categories": [ "math.FA", "math.CA", "math.SP" ], "abstract": "We present a class of weight functions $ w$ on the circle $ \\mathbb{T}$, called L\\'evy-Khinchin-Schoenberg (LKS) weights, for which we are able to completely characterize (in terms of a capacitary inequality) all Fourier multipliers for the weighted space $ L^{2}(\\mathbb{T},w)$. We show that the multiplier algebra is nontrivial if and only if $ 1/w\\in L^{1}(\\mathbb{T})$, and in this case multipliers satisfy the Spectral Localization Property (no \"hidden spectrum\"). On the other hand, the Muckenhoupt $ (A_{2})$ condition responsible for the basis property of exponentials $ (e^{ikx})$ is more or less independent of the Spectral Localization Property and LKS requirements. Some more complicated compositions of LKS weights are considered as well.", "revisions": [ { "version": "v1", "updated": "2014-04-16T20:27:59.000Z", "abstract": "We present a class of weight functions $ w$ on the circle $ \\mathbb{T}$, called L\\'evy-Khinchin-Schoenberg ({\\rm LKS}) weights, for which we are able to completely characterize (in terms of a capacitary inequality) all Fourier multipliers for the weighted space $ L^{2}(\\mathbb{T},w)$. We show that the multiplier algebra is nontrivial if and only if $ 1/w\\in L^{1}(\\mathbb{T})$, and in this case multipliers satisfy the Spectral Localization Property (no \"hidden spectrum\"). On the other hand, the Muckenhoupt $ (A_{2})$ condition responsible for the basis property of exponentials $ (e^{ikx})$ is more or less independent of the Spectral Localization Property and {\\rm LKS} requirements. Some more complicated compositions of {\\rm LKS} weights are considered as well.", "comment": "47 pages", "journal": null, "doi": null }, { "version": "v2", "updated": "2015-09-28T16:33:57.000Z" } ], "analyses": { "subjects": [ "42B15", "46B15", "47A10" ], "keywords": [ "fourier multipliers", "lévy-khinchin-schoenberg weights", "spectral localization property", "case multipliers satisfy", "capacitary inequality" ], "note": { "typesetting": "TeX", "pages": 47, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1404.4380N" } } }