Algebra of Fields on the Light Cone

A consistent light-cone formulation of the algebra of fields is derived by the use of Schwinger's quantum action principle. The current commutators are extracted from the theory for a massive Yang-Mills field interacting with fermions by an invariant coupling. Deep-inelastic scaling sum rules are found which are formally valid and which relate F₂(w) [=FL(w)] to the Fourier transform of the diagonal matrix elements of a bilocal operator. In addition, fixed-mass sum rules (valid if Class-II graphs do not contribute) are derived. These relate integrals of various structure functions to the bilocal operator mentioned above. In the Born approximation these fixed-mass sum rules are not valid, except at the physically interesting point q²=0.