A bijection between shrubs and series-parallel posets
نویسنده
چکیده
Motivated by the theory of operads, we introduce new combinatorial objects, called shrubs, that generalize forests of rooted trees. We show that the species of shrubs is isomorphic to the species of series-parallel posets. Résumé. Motivé par des considérations sur les opérades, on introduit de nouveaux objets combinatoires, appelés arbustes, qui généralisent les forêts d’arbres enracinés. On montre que l’espèce des arbustes est isomorphe à l’espèce des posets Série-Parallèle.
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