We construct a new kind of path integral for the Dirac equation propagator,
intended as an extension to 3 space dimensions of the Feynman "checkerboar
d" propagator. One form of this path integral is a "projector path" summati
on, out of which one can reconstruct standard 3D space and chirality. Other
forms allow the particle velocity along the path to be adjusted. (C) 2000
Academic Press.