I.F.T.

Almuerzo-Seminario

(Lunch seminar)

February 10th 1999, 14:00 p.m.

The Kreimer Hopf Algebra of Perturbative Field Theory and Noncommutative Geometry

José Mariano Gracia-Bondía

U. Zaragoza

The Hopf algebra of ``rooted trees" discovered by Dirk Kreimer codifies combinatorial and cohomological aspects of renormalization in quantum field theory, as well as the analytical behaviour of the Green functions under change of scales. An introduction to Kreimer's algebra is given, emphasizing its (still somewhat mysterious) essential coincidence with the algebra introduced by Alain Connes and Henri Moscovici to simplify the ``local" formula for the noncommutative index theorem, in the context of diffeomorphism equivariant geometries.

The almuerzo-seminario is intended to be an informal seminar and an open forum for discussion.

You are wellcome to bring your own bocata (sandwich), or coffee or tea.

Where: Modulo C-XVI, 3rd floor, Facultad de Ciencias U.A.M., C.U. Cantoblanco, 28049-Madrid