Sufficient conditions are established for the product of two ranked partially ordered sets to have the Sperner property. As a consequence, it is shown that the class of strongly Sperner rank-unimodal rank-symmetric partially ordered sets is closed under the operation of product. Counterexamples are
The Sperner property for posets: A probabilistic approach
β Scribed by J.P Dion
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 379 KB
- Volume
- 53
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
Dedicated to E. Corominas
Motivated by the problem of estimating the age (in generations) of a population that evolves according to the Galton-Watson process, we consider graded partially ordered sets on which a probability measure is defined. By looking at the antichain of maximal probability, one derives a new proof of Sperncr's lemma (1928) on the subsets of a set. More importantly, the technique of proof lends itself to generalizations to infinite posets and provides suitident conditions on the probability measure and the order relation so that the poset has the Sperner property and\or the rank unimodality. These results are extended to k-families and the strong Sperner property and related to some work by Erd6s (1945), Dilworth (1950), Baker (1969), Kleitman, Edelberg and Lubell (1971), Greene and Kleitman (1976), Stanley (1980), Griggs (1980), and Pouzet and Rosenberg (1981).
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