A Catalog of Enumeration Formulas for Bouquet and Dipole Embeddings Under Symmetries

TL;DR

This paper develops a comprehensive algebraic framework using Burnside's Lemma to enumerate bouquet and dipole embeddings under various symmetries, unifying existing formulas and deriving new ones relevant to multiple scientific fields.

Contribution

It introduces a unified counting framework for cellular embeddings with symmetries, providing new formulas for colored bouquets, directed embeddings, and vertex-labeled dipoles.

Findings

Unified enumeration formulas for bouquet and dipole embeddings.

New formulas for colored bouquets and directed embeddings.

Catalog of 58 sequences, 43 of which are novel.

Abstract

Motivated by a problem arising out of DNA origami, we give a general counting framework and enumeration formulas for various cellular embeddings of bouquets and dipoles under different kinds of symmetries. Our algebraic framework can be used constructively to generate desired symmetry classes, and we use Burnside's Lemma with various symmetry groups to derive the enumeration formulas. Our results assimilate several existing formulas into this unified framework. Furthermore, we provide new formulas for bouquets with colored edges (and thus for bouquets in nonorientable surfaces) as well as for directed embeddings of directed bouquets. We also enumerate vertex-labeled dipole embeddings. Since dipole embeddings may be represented by permutations, the formulas also apply to certain equivalence classes of permutations and permutation matrices. The resulting bouquet and dipole symmetry formulas enumerate structures relevant to a wide variety of areas in addition to DNA origami, including RNA secondary structures, Feynman diagrams, and topological graph theory. For uncolored objects we catalog 58 distinct sequences, of which 43 have not, as far as we know, been described previously.