Tubings, chord diagrams, and Dyson–Schwinger equations

Abstract

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 transparent in the sense that each tubing has a straightforward contribution. The Dyson–Schwinger equations solved here are more general than those previously solved by chord diagram techniques, including systems and noninteger values of the insertion parameter $s$. We remark on interesting combinatorial connections and properties.