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SYSTEMS OF ISLANDS WITH CONTINUOUS HEIGHT FUNCTIONS

Published online by Cambridge University Press:  01 May 2013

ZSOLT LENGVÁRSZKY*
Affiliation:
Department of Mathematics, Louisiana State University Shreveport, 1 University Place, Shreveport, LA 71115, USA
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Abstract

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We investigate island systems with continuous height functions and strongly laminar systems which are laminar systems containing sets with disjoint boundaries. In the discrete case, we show that for a maximal rectangular system of islands $ \mathcal{H} $ on an $m$ by $n$ rectangular grid we have $\lceil \min (m, n)/ 4\rceil \leq \vert \mathcal{H} \vert \leq \lceil m/ 2\rceil \lceil n/ 2\rceil $. In the continuous case we show that under some conditions maximal strongly laminar systems $ \mathcal{H} $ have cardinality ${\aleph }_{0} $ or ${2}^{{\aleph }_{0} } $ and present examples with $\vert \mathcal{H} \vert = {\aleph }_{0} $.

Type
Research Article
Copyright
Copyright ©2013 Australian Mathematical Publishing Association Inc. 

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