Multipoint Padé approximants to complex Cauchy transforms with polar singularities

نویسندگان

  • Laurent Baratchart
  • Maxim Yattselev
چکیده

We study diagonal multipoint Padé approximants to functions of the form F (z) = Z dλ(t) z − t +R(z), where R is a rational function and λ is a complex measure with compact regular support included in R, whose argument has bounded variation on the support. Assuming that interpolation sets are such that their normalized counting measures converge sufficiently fast in the weak-star sense to some conjugate-symmetric distribution σ, we show that the counting measures of poles of the approximants converge to b σ, the balayage of σ onto the support of λ, in the weak∗ sense, that the approximants themselves converge in capacity to F outside the support of λ, and that the poles of R attract at least as many poles of the approximants as their multiplicity and not much more. AMS Classification (MSC2000): primary 41A20, 41A30, 42C05; secondary 30D50, 30D55, 30E10, 31A15.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Meromorphic Approximants to Complex Cauchy Transforms with Polar Singularities

We study AAK-type meromorphic approximants to functions of the form F (z) = ∫ dλ(t ) z − t +R(z), where R is a rational function and λ is a complex measure with compact regular support included in (−1,1), whose argument has bounded variation on the support. The approximation is understood in Lp -norm of the unit circle, p ≥ 2. We dwell on the fact that the denominators of such approximants sati...

متن کامل

Meromorphic Approximants to Complex Cauchy Transforms with Polar Singularities

We study AAK-type meromorphic approximants to functions of the form F (z) = Z dλ(t) z − t +R(z), where R is a rational function and λ is a complex measure with compact regular support included in (−1, 1), whose argument has bounded variation on the support. The approximation is understood in L-norm of the unit circle, p ≥ 2. We dwell on the fact that the denominators of such approximants satisf...

متن کامل

Convergent Interpolation to Cauchy Integrals over Analytic Arcs

We consider multipoint Padé approximation to Cauchy transforms of complex measures. We show that if the support of a measure is an analytic Jordan arc and if the measure itself is absolutely continuous with respect to the equilibrium distribution of that arc with Dini-smooth non-vanishing density, then the diagonal multipoint Padé approximants associated with appropriate interpolation schemes c...

متن کامل

Strong Asymptotics of Hermite-padé Approximants for Angelesco Systems

In this work type II Hermite-Padé approximants for a vector of Cauchy transforms of smooth Jacobi-type densities are considered. It is assumed that densities are supported on mutually disjoint intervals (an Angelesco system with complex weights). The formulae of strong asymptotics are derived for any ray sequence of multi-indices.

متن کامل

Convergent interpolation to Cauchy integrals over analytic arcs with Jacobi-type weights

We design convergent multipoint Padé interpolation schemes to Cauchy transforms of non-vanishing complex densities with respect to Jacobi-type weights on analytic arcs, under mild smoothness assumptions on the density. We rely on the work [10] for the choice of the interpolation points, and dwell on the Riemann-Hilbert approach to asymptotics of orthogonal polynomials introduced in [33] in the ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of Approximation Theory

دوره 156  شماره 

صفحات  -

تاریخ انتشار 2009