2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/53577In this talk I want to explain the operator substractions needed to regularize gauge currents in a second quantized theory. The case of space-time dimension $3+1$ is considered in detail. In presence of chiral fermions the regularization effects a modification of the local commutation relations of the currents by local Schwinger terms. In $1+1$ dimensions one gets the usual central extension (Schwinger term does not depend on background gauge field) whereas in $3+1$ dimensions one gets an anomaly linear in the background potential.10pp, talk at the conference "Constraint theory and quantization", Montepulciano, June 1993, written in AMSTEX formatHigh Energy Physics - Theorytext