368 research outputs found

    Asymptotics of polynomials orthogonal over circular multiply connected domains

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    Let DD be a domain obtained by removing, out of the unit disk {z:∣z∣<1}\{z:|z|<1\}, finitely many mutually disjoint closed disks, and for each integer n≥0n\geq 0, let Pn(z)=zn+⋯P_n(z)=z^n+\cdots be the monic nnth-degree polynomial satisfying the planar orthogonality condition ∫DPn(z)zm‾dxdy=0\int_D P_n(z)\overline{z^m}dxdy=0, 0≤m<n0\leq m<n. Under a certain assumption on the domain DD, we establish asymptotic expansions and formulae that describe the behavior of Pn(z)P_n(z) as n→∞n\to\infty at every point zz of the complex plane. We also give an asymptotic expansion for the squared norm ∫D∣Pn∣2dxdy\int_D|P_n|^2dxdy

    Strong Asymptotics of Hermite-Pad\'e Approximants for Angelesco Systems

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    In this work type II Hermite-Pad\'e 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.Comment: 40 page
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