{ "id": "1506.07162", "version": "v1", "published": "2015-06-23T19:57:09.000Z", "updated": "2015-06-23T19:57:09.000Z", "title": "On the density of polynomials under perturbations of the measure", "authors": [ "Rafael del Rio", "Luis O. Silva" ], "comment": "12 pages, no figures", "categories": [ "math-ph", "math.MP" ], "abstract": "We prove that if the polynomials are dense in $L_2(\\mathbb{R}, \\rho)$, then they are dense in $L_2(\\mathbb{R}, \\rho+\\mu)$ where $\\mu$ is a measure supported on a finite set of points. In particular, it will follow that $ \\rho+\\mu$ is a spectral measure of a Jacobi operator if $\\rho$ is. These results are obtained through the analysis of the Green functions of Jacobi operators.", "revisions": [ { "version": "v1", "updated": "2015-06-23T19:57:09.000Z" } ], "analyses": { "subjects": [ "41A10", "47B36", "33E30" ], "keywords": [ "polynomials", "jacobi operator", "perturbations", "finite set" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150607162D" } } }