Garza, LuisHernández, JavierMarcellán Español, Francisco José2009-12-022009-12-022010-01Journal of Computational and Applied Mathematics, 2010, vol. 233, n. 5, p. 1220-12310377-0427https://hdl.handle.net/10016/590812 pages, no figures.-- MSC2000 codes: 42C05, 15A23.-- Published in Special Issue dedicated to William B. Gragg on the occasion of his 70th birthday.In this paper we analyze a perturbation of a nontrivial positive measure supported on the unit circle. This perturbation is the inverse of the Christoffel transformation and is called the Geronimus transformation. We study the corresponding sequences of monic orthogonal polynomials as well as the connection between the associated Hessenberg matrices. Finally, we show an example of this kind of transformation.application/pdfeng© ElsevierMeasures on the unit circleOrthogonal polynomialsSpectral transformationsHessenberg matricesresearch articleMatemáticas10.1016/j.cam.2007.11.023open access