From Feynman's triangle to Feynman's tetrahedra


Silvano Rossetto, Giovanni Vincenzi




We investigate a natural extension of so called planar $t$-Feynman configurations, referring to triangles, to three dimensional $t$-Feynman configurations, referring to tetrahedra. Our main result extends to three dimensions the well-known Routh's formula for planar $t$-Feynman configurations.