Improved analytic techniques for tree graph calculations and the ggqanti qlanti l subprocess

We demonstrate further improvements in the CALCUL approach to tree graph calculations. We employ polarization vectors referenced to a single momentum and obtain expressions in terms of spinor inner products. The method is crossing symmetric and can be easily implemented as an algebraic computer program. As an illustration we present an analytic calculation of the ggqanti q'lanti l' subprocess in the standard model where lanti l' can be in either the charged or the neutral channel. (orig.)