Intrinsic interpolation, near-circularity and maximal convergence

Let E be compact and connected with capE>0 and connected complement Ω=ℂ¯∖E, let gΩ(z,∞) be the Green’s function of Ω with pole at infinity and let Eσ≔{z∈Ω:gΩ(z,∞)<logσ}∪E,1<σ<∞, be the Green domains with boundaries Γσ. Let f be holomorphic on E and let ρ(f) denote the maximal parameter o...

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Published in:Journal of approximation theory Vol. 312; p. 106201
Main Author: Blatt, Hans-Peter
Format: Journal Article
Language:English
Published: Elsevier Inc 01.12.2025
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ISSN:0021-9045
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Abstract Let E be compact and connected with capE>0 and connected complement Ω=ℂ¯∖E, let gΩ(z,∞) be the Green’s function of Ω with pole at infinity and let Eσ≔{z∈Ω:gΩ(z,∞)<logσ}∪E,1<σ<∞, be the Green domains with boundaries Γσ. Let f be holomorphic on E and let ρ(f) denote the maximal parameter of holomorphy of f and let pnn∈N be a sequence of polynomials converging maximally to f on E. If σ, 1<σ<ρ(f)<∞, is fixed and if mn(σ) denotes the number of interpolation points of pn to f in Eσ with normalized counting measure μσ,n, then there exists a subset Λ⊂N such that mn(σ)=n+o(n)asn∈Λ,n→∞,μσ,n|Ê+μσ,n|Ω⟶∗μEasn∈Λ,n→∞, where μσ,n=μσ,n|E+μσ,n|Ω, μσ,n|Ê denotes the balayage measure of μσ,n|E onto the boundary of E and μE is the equilibrium measure of E. Moreover, there exists a sequence σnn∈Λ converging to σ such that the closed curves γn=(f−pn)(Γσn) do not pass through the point 0 and the winding numbers Indγn(0) satisfy Indγn(0)=mn(σn)=n+o(n)asn∈Λ,n→∞.
AbstractList Let E be compact and connected with capE>0 and connected complement Ω=ℂ¯∖E, let gΩ(z,∞) be the Green’s function of Ω with pole at infinity and let Eσ≔{z∈Ω:gΩ(z,∞)<logσ}∪E,1<σ<∞, be the Green domains with boundaries Γσ. Let f be holomorphic on E and let ρ(f) denote the maximal parameter of holomorphy of f and let pnn∈N be a sequence of polynomials converging maximally to f on E. If σ, 1<σ<ρ(f)<∞, is fixed and if mn(σ) denotes the number of interpolation points of pn to f in Eσ with normalized counting measure μσ,n, then there exists a subset Λ⊂N such that mn(σ)=n+o(n)asn∈Λ,n→∞,μσ,n|Ê+μσ,n|Ω⟶∗μEasn∈Λ,n→∞, where μσ,n=μσ,n|E+μσ,n|Ω, μσ,n|Ê denotes the balayage measure of μσ,n|E onto the boundary of E and μE is the equilibrium measure of E. Moreover, there exists a sequence σnn∈Λ converging to σ such that the closed curves γn=(f−pn)(Γσn) do not pass through the point 0 and the winding numbers Indγn(0) satisfy Indγn(0)=mn(σn)=n+o(n)asn∈Λ,n→∞.
ArticleNumber 106201
Author Blatt, Hans-Peter
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Cites_doi 10.1007/BF02559510
10.7146/math.scand.a-10741
10.1007/s00365-022-09564-7
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Keywords Weak convergence
Interpolation
30E10
Condenser
Complex approximation
41A10
Near-circularity
Equilibrium measure
Maximal convergence
41A05
Language English
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Snippet Let E be compact and connected with capE>0 and connected complement Ω=ℂ¯∖E, let gΩ(z,∞) be the Green’s function of Ω with pole at infinity and let...
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StartPage 106201
SubjectTerms Complex approximation
Condenser
Equilibrium measure
Interpolation
Maximal convergence
Near-circularity
Weak convergence
Title Intrinsic interpolation, near-circularity and maximal convergence
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