Gauge theories and axial gauge

This work is on gauge theories and the renormalization. Chapters 1,2,3 are on action principles, on abelian gauge theories and on non-abelian gauge theories. A perturbation theory is used. The main results are in chapter 4 on axial gauge and extended Becchi-Rouet-Stora transformation. Base-independent methods motivated by differential geometry are used. The general solution of the Slavnov identity is given in the tree approximation. To investigate the dependence of the whole theory - including its unphysical part - on the four-vector n the BRS transformation is extended, and the four-vector n is transformed into a Grassmann-valued four-vector Χ. Thus the n dependence becomes a part of the Slavnov identity and can be traced term by term through the perturbation series. 10 refs. (qui)