Light Cone as Seen in the Gluon Model

To second order in a gluon model, the longitudinal electroproduction function respects scaling and thus provides a laboratory for the study of various light-cone theorems recently derived in the literature. In particular, the operator-Schwinger-term sum rule is upheld by a hitherto unsuspected singularity at $\omega \left(\equiv \frac{-q^2}{2\nu }\right)=0\mathrm{}$ which may obliterate any direct connection between light-cone singularities and electroproduction experiments. We also discuss the use of causal representations in the literature of deep inelastic processes emphasizing the delicacy of popular techniques.