Recovering Orthogonality from Quasi-nature of Spectral Transformations

In this contribution, quasi-orthogonality of polynomials generated by Geronimus and Uvarov transformations is analyzed. An attempt is made to discuss the recovery of the source orthogonal polynomial from the quasi-Geronimus and quasi-Uvarov polynomials of order one. Moreover, the discussion on the difference equation satisfied by quasi-Geronimus and quasi-Uvarov polynomials is presented. Furthermore, the orthogonality of quasi-Geronimus and quasi-Uvarov polynomials is achieved through the reduction of the degree of coefficients in the difference equation. During this procedure, alternative representations of the parameters responsible for achieving orthogonality are derived. One of these representations involves the Stieltjes transform of the measure. Finally, the recurrence coefficients ensuring the existence of a measure that makes the quasi-Geronimus Laguerre polynomial of order one an orthogonal polynomial are calculated.

orthogonal polynomials and linear functionals; linear spectral transformations; quasi-orthogonal polynomials; recurrence relations; transfer matrix; stieltjes transform; continued fraction; primary 42c05; 33c45; 26c10; 11a55

Recovering Orthogonality from Quasi-nature of Spectral Transformations Articles