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arXiv · 1208.5993

Γ-species and the enumeration of k-trees

Andrew Gainer-Dewar
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Abstract

We study the class of graphs known as k-trees through the lens of Joyal's theory of combinatorial species (and an equivariant extension known as '$Γ$-species' which incorporates data about 'structural' group actions). This culminates in a system of recursive functional equations giving the generating function for unlabeled k-trees which allows for fast, efficient computation of their numbers. Enumerations up to k = 10 and n = 30 (for a k-tree with (n+k-1) vertices) are included in tables, and Sage code for the general computation is included in an appendix.

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Andrew Gainer-Dewar. 2012-12-12. Γ-species and the enumeration of k-trees. https://arxiv.org/abs/1208.5993

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