Journal of Applied Mathematics 
Volume 1 (2001), Issue 2, Pages 69-90
doi:10.1155/S1110757X01000225

Quasi-definiteness of generalized Uvarov transforms of moment functionals

D. H. Kim and K. H. Kwon

Division of Applied Mathematics, Korea Advanced Institute of Science and Technology, Taejon 305-701, Korea

Received 11 March 2001

Abstract

When σ is a quasi-definite moment functional with the monic orthogonal polynomial system {Pn(x)}n=0, we consider a point masses perturbation τ of σ given by τ:=σ+λΣl=1mΣk=0ml((1)kulk/k!)δ(k)(xcl), where λ,ulk, and cl are constants with cicj for ij. That is, τ is a generalized Uvarov transform of σ satisfying A(x)τ=A(x)σ, where A(x)=l=1m(xcl)ml+1. We find necessary and sufficient conditions for τ to be quasi-definite. We also discuss various properties of monic orthogonal polynomial system {Rn(x)}n=0 relative to τ including two examples.