{ "id": "1608.04114", "version": "v1", "published": "2016-08-14T17:06:25.000Z", "updated": "2016-08-14T17:06:25.000Z", "title": "Approximation by polynomials in Sobolev spaces with Jacobi weight", "authors": [ "Yuan Xu" ], "categories": [ "math.CA", "math.NA" ], "abstract": "Polynomial approximation is studied in the Sobolev space $W_p^r(w_{\\alpha,\\beta})$ that consists of functions whose $r$-th derivatives are in weighted $L^p$ space with the Jacobi weight function $w_{\\alpha,\\beta}$. This requires simultaneous approximation of a function and its consecutive derivatives up to $s$-th order with $s \\le r$. We provide sharp error estimates given in terms of $E_n(f^{(r)})_{L^p(w_{\\alpha,\\beta})}$, the error of best approximation to $f^{(r)}$ by polynomials in $L^p(w_{\\alpha,\\beta})$, and an explicit construction of the polynomials that approximate simultaneously with the sharp error estimates.", "revisions": [ { "version": "v1", "updated": "2016-08-14T17:06:25.000Z" } ], "analyses": { "subjects": [ "41A10", "41A25", "42C05", "42C10", "33C45" ], "keywords": [ "sobolev space", "sharp error estimates", "jacobi weight function", "th derivatives", "th order" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }