Generalized retarded products
John Charlton Polkinghorne · Proceedings of the Royal Society of London A Mathematical and Physical Sciences · 1958
Abstract The generalization of the retarded commutator previously introduced (Polkinghorne 1957b) is discussed. A proof of its causal property is given and a new proof of its relation to S-matrix elements is given. This latter provides a generalization of the work of Lehmann, Symanzik & Zimmermann (1957).