6533b862fe1ef96bd12c60cd

RESEARCH PRODUCT

Compactness of a conformal boundary of the Euclidean unit ball

Päivi Lammi

subject

CombinatoricsUnit sphereCompact spaceLogarithmGeneral MathematicsMathematical analysisEuclidean geometryMetric (mathematics)Boundary (topology)Conformal mapMathematicsHarnack's inequality

description

We study conformal metrics d‰ on the Euclidean unit ball B n : We assume that either the density ‰ associated with the metric d‰ satisfies a logarithmic volume growth condition for small balls or that ‰ satisfies a Harnack inequality and a suitable sub-Euclidean volume growth condition. We prove that the ‰-boundary @‰ B n is homeomorphic to S ni1 if and only if @‰ B n is compact. In the planar case, the compactness of @‰ B 2 is further equivalent to local connectivity of the ‰-boundary together with the boundedness of (B 2 ;d‰):

https://doi.org/10.5186/aasfm.2011.3601