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Abstract
A semilattice tree T with 0 is slim if there is a chain C with 0 so that the lattices θ (T) and θ(C) of semilattice congruences are isomorphic. This paper establishes elementary consequences of slimness and uses simple constructive techniques to show certain small trees slim. If T is the union of at most countably many branches, each of which has a maximum or a countable cotinal subset, then T is slim. For trees with enough maximals slimness is equivalent with not having any uncountable anti-chains. If a tree T has a countable cofinal subset then T is slim. Thus finitary trees are slim.
MSC classification
- Type
- Research Article
- Information
- Journal of the Australian Mathematical Society , Volume 30 , Issue 2 , December 1980 , pp. 201 - 214
- Copyright
- Copyright © Australian Mathematical Society 1980
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