Geometrical splitting and reduction of Feynman diagrams
  A geometrical approach to the calculation of N-point Feynman diagrams is reviewed. It is shown that the geometrical splitting yields useful connections between Feynman integrals with different momenta and masses. It is demonstrated how these results can be used to reduce the number of variables in the occurring functions. 
Andrei I. Davydychev
hep-th hep-ph math-ph math.MP