The Feynman Legacy

The Euler characteristic of graph complexes via Feynman diagrams

We prove several claims made by Kontsevich about the orbifold Euler characteristic of the three types of graph homology introduced by him. For this purpose, first we develop a simplified version of the Feynman diagram method, which requires integrals in one variable only, to obtain the generating functions as asymptotic expansions of certain Gaussian integrals. Finally, following Penner, we relate these integrals to the gamma function in order to compute the individual coefficients of the generating functions.

Invariant Differential Forms on Complexes of Graphs and Feynman Integrals

We study differential forms on an algebraic compactification of a moduli space of metric graphs. Canonical examples of such forms are obtained by pulling back invariant differentials along a tropical Torelli map. The invariant differential forms in question generate the stable real cohomology of the general linear group, as shown by Borel. By integrating such invariant forms over the space of metrics on a graph, we define canonical period integrals associated to graphs, which we prove are always finite and take the form of generalised Feynman integrals. Furthermore, canonical integrals can be …

图积分、费曼周期与单值多重zeta值

Graph integrals, Feynman periods, and single-valued multiple zeta values

研究图积分是什么数的问题，通过证明原始规范积分与变形量子化中的复位置空间积分一致，得出图的规范积分值为单值多重zeta值，且每个单值多重zeta值是特定图费曼周期的有理线性组合，还表明在交换图复形中相关上闭链一致。

循环 operad 图复形的权 2 上同调与柄体群

Weight 2 cohomology of graph complexes of cyclic operads and the handlebody group

本文计算了多个循环（余）operad 费曼变换的权 2 及权 top$-2$ 上同调，利用 Giansiracusa 结果得到柄体群的权 top$-2$ 上同调，并与曲线模空间相关结果比较，还为柄体群权 top 上同调与 Kontsevich 图上同调等价提供新证明。