0000000000114808

AUTHOR

Raimo Näkki

showing 11 related works from this author

Cluster sets and quasiconformal mappings

2010

Certain classical results on cluster sets and boundary cluster sets of analytic functions, due to Iversen, Lindelof, Noshiro, Tsuji, Ohtsuka, Pommerenke, Carmona, Cufi and others, are extended to n-dimensional quasiconformal mappings. Unlike what is usually the case in the context of analytic functions, our considerations are not restricted to mappings of a disk or ball only. It is shown, for instance, that quasiconformal cluster sets and boundary cluster sets, taken at a non-isolated boundary point of an arbitrary domain, coincide. More refined versions are established in the special case where the domain is the open unit ball. These include cluster set considerations of the induced radial…

Discrete mathematicsComputational MathematicsNumerical AnalysisOpen unitApplied MathematicsBoundary (topology)Ball (mathematics)Boundary extensionSpecial caseAnalysisAnalytic functionMathematicsComplex Variables and Elliptic Equations
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Quasiconformal distortion on arcs

1994

Distortion (mathematics)Quasiconformal mappingExtremal lengthPartial differential equationGeneral MathematicsMathematical analysisTopologyAnalysisMathematicsJournal d'Analyse Mathématique
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Boundary angles, cusps and conformal mappings

1986

Let f be a conformal mapping of a bounded Jordan domain D in the complex plane onto the unit disk . This paper examines the consequences for the local geometry of D near a boundary point z 0 of the mapping f-or, to be more precise, of the homeomorphic extension of this mapping to the closure of D—satisfying a Holder condition at z 0 or, alternatively, of its inverse satisfying a Holder condition at the point f(z 0). In particular, the compatibility of Holder conditions with the presence of cusps in the boundary of D is investigated.

Bounded functionMathematical analysisHölder conditionInverseBoundary (topology)Conformal mapGeometryGeneral MedicineUnit diskComplex planeMathematicsComplex Variables, Theory and Application: An International Journal
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Extremal length and Hölder continuity of conformal mappings

1986

Extremal lengthGeneral MathematicsMathematical analysisHölder conditionBoundary conformal field theoryConformal mapModulus of continuityMathematicsCommentarii Mathematici Helvetici
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Boundary modulus of continuity and quasiconformal mappings

2012

Let D be a bounded domain in R n , n ‚ 2, and let f be a continuous mapping of D into R n which is quasiconformal in D. Suppose that jf(x) i f(y)j • !(jx i yj) for all x and y in @D, where ! is a non-negative non-decreasing function satisfying !(2t) • 2!(t) for t ‚ 0. We prove, with an additional growth condition on !, that jf(x) i f(y)jC maxf!(jx i yj);jx i yj fi g

Pure mathematicsGeneral MathematicsBounded function010102 general mathematicsDomain (ring theory)Boundary (topology)Geometry010103 numerical & computational mathematicsFunction (mathematics)0101 mathematics01 natural sciencesModulus of continuityMathematicsAnnales Academiae Scientiarum Fennicae Mathematica
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Asymptotic values and hölder continuity of quasiconformal mappings

1987

Quasiconformal mappingPartial differential equationTriangle inequalityGeneral MathematicsMathematical analysisHölder conditionAnalysisMathematicsJournal d'Analyse Mathématique
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Lipschitz conditions,b-arcwise connectedness and conformal mappings

1982

Discrete mathematicsExtremal lengthPartial differential equationLipschitz domainFunctional analysisSocial connectednessGeneral MathematicsConformal mapLipschitz continuityAnalysisMathematicsJournal d'Analyse Mathématique
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Boundary Hölder Continuity and Quasiconformal Mappings

1991

Quasiconformal mappingGeneral MathematicsMathematical analysisHölder conditionBoundary (topology)Modulus of continuityMathematicsJournal of the London Mathematical Society
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Cone conditions and quasiconformal mappings

1988

Let f be a quasiconformal mapping of the open unit ball B n = {x ∈ R n : | x | < l× in euclidean n-space R n onto a bounded domain D in that space. For dimension n= 2 the literature of geometric function theory abounds in results that correlate distinctive geometric properties of the domain D with special behavior, be it qualitative or quantitative, on the part of f or its inverse. There is a more modest, albeit growing, body of work that attempts to duplicate in dimensions three and above, where far fewer analytical tools are at a researcher’s disposal, some of the successes achieved in the plane along such lines. In this paper we contribute to that higher dimensional theory some observati…

Quasiconformal mappingPure mathematicsGeometric measure theoryGeometric function theoryBounded functionHölder conditionConformal mapBall (mathematics)Modulus of continuityMathematics
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Boundary regularity and the uniform convergence of quasiconformal mappings

1979

Image domainQuasiconformal mappingGeneral MathematicsNormal convergenceUniform convergenceMathematical analysisBoundary (topology)Modes of convergenceCompact convergenceNormal familyMathematicsCommentarii Mathematici Helvetici
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Quasiconformally Bi-Homogeneous Compacta in the Complex Plane

1999

HomogeneousGeneral MathematicsGeometryComplex planeMathematicsProceedings of the London Mathematical Society
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