eprintid: 1719 rev_number: 6 eprint_status: archive userid: 46 dir: disk0/00/00/17/19 datestamp: 2013-09-13 11:34:55 lastmod: 2013-09-16 12:03:00 status_changed: 2013-09-13 11:34:55 type: article metadata_visibility: show creators_name: Gnecco, Giorgio creators_name: Sanguineti, Marcello creators_id: giorgio.gnecco@imtlucca.it creators_id: title: On a Variational Norm Tailored to Variable-Basis Approximation Schemes ispublished: pub subjects: QA75 divisions: CSA full_text_status: none keywords: ${cal L}_1$-norm, Approximation schemes, convex hulls, infinite-dimensional optimization, upper and lower bounds, variation with respect to a set abstract: A variational norm associated with sets of computational units and used in function approximation, learning from data, and infinite-dimensional optimization is investigated. For sets Gk obtained by varying a vector y of parameters in a fixed-structure computational unit K(-,y) (e.g., the set of Gaussians with free centers and widths), upper and lower bounds on the GK -variation norms of functions having certain integral representations are given, in terms of the £1-norms of the weighting functions in such representations. Families of functions for which the two norms are equal are described. date: 2011 date_type: published publication: IEEE Transactions on Information Theory volume: 57 number: 1 publisher: IEEE pagerange: 549-558 id_number: 10.1109/TIT.2010.2090198 refereed: TRUE issn: 0018-9448 official_url: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5673958&isnumber=5673678 citation: Gnecco, Giorgio and Sanguineti, Marcello On a Variational Norm Tailored to Variable-Basis Approximation Schemes. IEEE Transactions on Information Theory, 57 (1). pp. 549-558. ISSN 0018-9448 (2011)