Feynman rules for theδexpansion

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Abstract
In this paper we further develop a novel perturbation scheme for quantum field theory in which the form of the interaction is expanded about the free theory. A set of Feynman rules for the perturbation expansion is derived that does not require the introduction of the provisional Lagrangian used in earlier papers. The rules permit direct calculation to all orders in the δ expansion, and are almost identical to standard Feynman rules. Only the form of the propagator and the vertex function are changed.