Relating flat connections and polylogarithms on higher genus Riemann surfaces

TL;DR

This paper explores the relationship between two recent generalizations of classical polylogarithms to higher-genus Riemann surfaces, linking flat connections, iterated integrals, and automorphisms to unify different constructions.

Contribution

It provides explicit methods to relate meromorphic and non-meromorphic higher-genus polylogarithm constructions via gauge transformations and automorphisms.

Findings

Established correspondence between two higher-genus polylogarithm frameworks

Constructed explicit transformations linking different flat connections

Unified the theory of higher-genus polylogarithms on Riemann surfaces.

Abstract

In this work, we relate two recent constructions that generalize classical (genus-zero) polylogarithms to higher-genus Riemann surfaces. A flat connection valued in a freely generated Lie algebra on a punctured Riemann surface of arbitrary genus produces an infinite family of homotopy-invariant iterated integrals associated to all possible words in the alphabet of the Lie algebra generators. Each iterated integral associated to a word is a higher-genus polylogarithm. Different flat connections taking values in the same Lie algebra on a given Riemann surface may be related to one another by the composition of a gauge transformation and an automorphism of the Lie algebra, thus producing closely related families of polylogarithms. In this paper we provide two methods to explicitly construct this correspondence between the meromorphic multiple-valued connection introduced by Enriquez in e-Print 1112.0864 and the non-meromorphic single-valued and modular-invariant connection introduced by D'Hoker, Hidding and Schlotterer, in e-Print 2306.08644.