4 papers
Non-commutative Hopf algebra of formal diffeomorphisms
Christian Brouder, Alessandra Frabetti, Christian Krattenthaler
The subject of this paper are two Hopf algebras which are the non-commutative analogues of two different groups of formal power series. The first group is the set of invertible ser…
QED Hopf algebras on planar binary trees
Christian Brouder, Alessandra Frabetti
In this paper we describe the Hopf algebras on planar binary trees used to renormalize the Feynman propagators of quantum electrodynamics, and the coaction which describes the reno…
Noncommutative renormalization for massless QED
Christian Brouder, Alessandra Frabetti
We study the renormalization of massless QED from the point of view of the Hopf algebra discovered by D. Kreimer. For QED, we describe a Hopf algebra of renormalization which is ne…
On the Leibniz cohomology of vector fields
Alessandra Frabetti, Friedrich Wagemann
I. M. Gelfand and D. B. Fuks have studied the cohomology of the Lie algebra of vector fields on a manifold. In this article, we generalize their main tools to compute the Leibniz c…