{ "id": "math-ph/0501057", "version": "v1", "published": "2005-01-22T02:49:30.000Z", "updated": "2005-01-22T02:49:30.000Z", "title": "Orthogonal polynomials with discontinuous weights", "authors": [ "Yang Chen", "Gunnar Pruessner" ], "comment": "9 pages, 2 figures, JPA style", "journal": "J. Phys. A: Math. Gen. 38 (12), L191--L198 (2005)", "doi": "10.1088/0305-4470/38/12/L01", "categories": [ "math-ph", "math.MP", "nlin.SI" ], "abstract": "In this paper we present a brief description of a ladder operator formalism applied to orthogonal polynomials with discontinuous weights. The two coefficient functions, A_n(z) and B_n(z), appearing in the ladder operators satisfy the two fundamental compatibility conditions previously derived for smooth weights. If the weight is a product of an absolutely continuous reference weight w_0 and a standard jump function, then A_n(z) and B_n(z) have apparent simple poles at these jumps. We exemplify the approach by taking w_0 to be the Hermite weight. For this simpler case we derive, without using the compatibility conditions, a pair of difference equations satisfied by the diagonal and off-diagonal recurrence coefficients for a fixed location of the jump. We also derive a pair of Toda evolution equations for the recurrence coefficients which, when combined with the difference equations, yields a particular Painleve IV.", "revisions": [ { "version": "v1", "updated": "2005-01-22T02:49:30.000Z" } ], "analyses": { "keywords": [ "orthogonal polynomials", "discontinuous weights", "difference equations", "standard jump function", "fundamental compatibility conditions" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }