Title
A rational Stieltjes moment problem
Abstract
Let {αk} be a sequence of points on the real axis, and let L denote the linear span of the set {1/ω0;,1/ω1, ...,1/ωn,...}, where ω0 = 1, ωn = (z - α1)(z - α2)... (z - αn) for n ≥ 1. A measure µ with support in an interval [γ, ∞) and with respect to which all functions in L . L are integrable induces an inner product in L and hence orthogonal rational functions {φn} and associated functions {σn} corresponding to the sequence {1/ωn}. Assuming certain constellations of the points {αk}, it is shown that the sequences {-σ2m(z)/φ2m(z)} and {-σ2m+1(z)/ φ2m+1(z)} are monotonic on a certain real interval (α,β) and convergent in the complex plane outside the interval [γ,∞) to functions F(z,µ(0)) and F(z, µ(∞)), where F(z, µ) denotes the Stieltjes transform ∫-∞∞ dµ(t)/(t - z) of a measure µ. Furthermore for every µ giving rise to the same integral values for functions in L . L, the inequality F(x,µ(0)) ≤ F(x,µ) ≤ F(x,µ(∞)) holds for x ∈ (α,β). These results are essentially generalizations of results concerning the strong (or two-point) Stieltjes moment problem, and are also similar to results concerning the classical Stieltjes moment problem.
Year
DOI
Venue
2002
10.1016/S0096-3003(01)00073-X
Applied Mathematics and Computation
Keywords
Field
DocType
Orthogonal rational functions,Rational moment problems
Monotonic function,Combinatorics,Linear span,Mathematical analysis,Complex plane,Stieltjes moment problem,Function composition,Rational function,Mathematics,Stieltjes transform
Journal
Volume
Issue
ISSN
128
2-3
0096-3003
Citations 
PageRank 
References 
3
1.42
0
Authors
4
Name
Order
Citations
PageRank
A. Bultheel111717.02
P. Gonzalez-Vera2153.58
E. Hendriksen3245.67
Olav NjåStad45612.34