{ "id": "2208.14779", "version": "v1", "published": "2022-08-31T11:34:44.000Z", "updated": "2022-08-31T11:34:44.000Z", "title": "Necessary and sufficient conditions for a family of continuous functions to form a Karhunen-Loève basis", "authors": [ "Ricardo Carrizo Vergara" ], "comment": "3 pages short result", "categories": [ "math.FA", "math.PR" ], "abstract": "Given an orthonormal system of $L^{2}(D)$ consistent of continuous functions $(f_{n})_{n}$, with $D \\subset \\mathbb{R}^{d}$ compact, and given a sequence of strictly positive coefficients $(\\lambda_{n})_{n}$ forming a convergent series, we prove that they consist in the eigenfunctions and eigenvectors of a covariance operator associated to a continuous positive-definite Kernel if and only if the sequence of partial sums $ \\sum_{j \\leq n} \\lambda_{j} f_{j}^{2} $ is equicontinuous over $D$.", "revisions": [ { "version": "v1", "updated": "2022-08-31T11:34:44.000Z" } ], "analyses": { "keywords": [ "continuous functions", "karhunen-loève basis", "sufficient conditions", "orthonormal system", "convergent series" ], "note": { "typesetting": "TeX", "pages": 3, "language": "en", "license": "arXiv", "status": "editable" } } }