{ "id": "2008.08079", "version": "v1", "published": "2020-08-18T17:59:25.000Z", "updated": "2020-08-18T17:59:25.000Z", "title": "Harmonic analysis of little $q$-Legendre polynomials", "authors": [ "Stefan Kahler" ], "comment": "The paper is essentially also a part of the first version of arXiv:1806.00339 [math.FA]. It is now a separate paper because the associated symmetric Pollaczek part of arXiv:1806.00339 [math.FA] was extended. Compared to the (first version of) arXiv:1806.00339, we extended and added some results on little $q$-Legendre polynomials", "categories": [ "math.FA" ], "abstract": "Many classes of orthogonal polynomials satisfy a specific linearization property giving rise to a polynomial hypergroup structure, which offers an elegant and fruitful link to harmonic and functional analysis. From the opposite point of view, this allows regarding certain Banach algebras as $L^1$-algebras, associated with underlying orthogonal polynomials or with the corresponding orthogonalization measures. The individual behavior strongly depends on these underlying polynomials. We study the little $q$-Legendre polynomials, which are orthogonal with respect to a discrete measure. Their $L^1$-algebras have been known to be not amenable but to satisfy some weaker properties like right character amenability. We will show that the $L^1$-algebras associated with the little $q$-Legendre polynomials share the property that every element can be approximated by linear combinations of idempotents. This particularly implies that these $L^1$-algebras are weakly amenable (i. e., every bounded derivation into the dual module is an inner derivation), which is known to be shared by any $L^1$-algebra of a locally compact group. As a crucial tool, we establish certain uniform boundedness properties of the characters. Our strategy relies on continued fractions, character estimations and asymptotic behavior.", "revisions": [ { "version": "v1", "updated": "2020-08-18T17:59:25.000Z" } ], "analyses": { "subjects": [ "33D45", "40A15", "43A20", "43A62" ], "keywords": [ "harmonic analysis", "specific linearization property giving rise", "orthogonal polynomials satisfy", "right character amenability", "uniform boundedness properties" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }