English

Subdivergence-free gluings of trees

Combinatorics 2025-01-13 v3

Abstract

A gluing of two rooted trees is an identification of their leaves and un-subdivision of the resulting 2-valent vertices. A gluing of two rooted trees is subdivergence free if it has no 2-edge cuts with both roots on the same side of the cut. The problem and language is motivated by quantum field theory. We enumerate subdivergence-free gluings for certain families of trees, showing a connection with connected permutations, and we give algorithms to compute subdivergence-free gluings.

Keywords

Cite

@article{arxiv.2106.07494,
  title  = {Subdivergence-free gluings of trees},
  author = {Xinle Dai and Jordan Long and Karen Yeats},
  journal= {arXiv preprint arXiv:2106.07494},
  year   = {2025}
}

Comments

minor edits according to referee comments, 20 pages