15,159 research outputs found
Embeddings of infinitely connected planar domains into C^2
We prove that every circled domain in the Riemann sphere admits a proper
holomorphic embedding to C^2. Our methods also apply to circled domains with
punctures, provided that all but finitely many of the punctures belong to the
closure of the set of complementary discs.Comment: Analysis and PDE, to appea
Finite convex geometries of circles
Let F be a finite set of circles in the plane. We point out that the usual
convex closure restricted to F yields a convex geometry, that is, a
combinatorial structure introduced by P. H Edelman in 1980 under the name
"anti-exchange closure system". We prove that if the circles are collinear and
they are arranged in a "concave way", then they determine a convex geometry of
convex dimension at most 2, and each finite convex geometry of convex dimension
at most 2 can be represented this way. The proof uses some recent results from
Lattice Theory, and some of the auxiliary statements on lattices or convex
geometries could be of separate interest. The paper is concluded with some open
problems.Comment: 22 pages, 7 figure
Asymptotics of generalized Hadwiger numbers
We give asymptotic estimates for the number of non-overlapping homothetic
copies of some centrally symmetric oval which have a common point with a
2-dimensional domain having rectifiable boundary, extending previous work
of the L.Fejes-Toth, K.Borockzy Jr., D.G.Larman, S.Sezgin, C.Zong and the
authors. The asymptotics compute the length of the boundary in the
Minkowski metric determined by . The core of the proof consists of a method
for sliding convex beads along curves with positive reach in the Minkowski
plane. We also prove that level sets are rectifiable subsets, extending a
theorem of Erd\"os, Oleksiv and Pesin for the Euclidean space to the Minkowski
space.Comment: 20p, 9 figure
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