5 papers
Subdivergence-free gluings of trees
Xinle Dai, Jordan Long, Karen Yeats
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 ha…
Hopf algebras from poset growth models
Karen Yeats, Stav Zalel
We give a framework for growth models on posets which simultaneously generalizes the Classical Sequential Growth models for posets from causal set theory and the tree growth models…
Limbs and Cospectral Vertices in Trees
Caelan Wang, Karen Yeats
We generalize Schwenk's result that almost all trees contain any given limb to trees with positive integer vertex weights. The concept of characteristic polynomial is extended to s…
Feynman symmetries of the Martin and invariants of regular graphs
Erik Panzer, Karen Yeats
For every regular graph, we define a sequence of integers, using the recursion of the Martin polynomial. This sequence counts spanning tree partitions and constitutes the diagonal…
Tubings, chord diagrams, and Dyson--Schwinger equations
Paul-Hermann Balduf, Amelia Cantwell, Kurusch Ebrahimi-Fard +3
We give series solutions to single insertion place propagator-type systems of Dyson--Schwinger equations using binary tubings of rooted trees. These solutions are combinatorially t…