The Fermat Cubic, Elliptic Functions, Continued Fractions, and a Combinatorial Excursion
Séminaire lotharingien de combinatoire, Tome 54 (2006-2007)
Citer cet article
Voir la notice de l'acte provenant de la source Séminaire Lotharingien de Combinatoire website
Elliptic functions considered by Dixon in the nineteenth century and related to Fermat's cubic, x3+y3=1, lead to a new set of continued fraction expansions with sextic numerators and cubic denominators. The functions and the fractions are pregnant with interesting combinatorics, including a special Pólya urn, a continuous-time branching process of the Yule type, as well as permutations satisfying various constraints that involve either parity of levels of elements or a repetitive pattern of order three. The combinatorial models are related to but different from models of elliptic functions earlier introduced by Viennot, Flajolet, Dumont, and Françon.