English

{\Gamma}-species and the enumeration of k-trees

Combinatorics 2015-09-14 v3

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\Gamma-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.

Keywords

Cite

@article{arxiv.1208.5993,
  title  = {{\Gamma}-species and the enumeration of k-trees},
  author = {Andrew Gainer-Dewar},
  journal= {arXiv preprint arXiv:1208.5993},
  year   = {2015}
}

Comments

26 pages; includes Python code