Geometrical methods in loop calculations and the three-point function

Abstract

A geometrical way to calculate N-point Feynman diagrams is reviewed. As an example, the dimensionally-regulated three-point function is considered, including all orders of its epsilon-expansion. Analytical continuation to other regions of the kinematical variables is discussed.

Comments: 6 pages, LaTeX, 3 eps figures, contribution to proceedings of ACAT2005 (Zeuthen, May 2005)