  This article is concerned with compositions in the context of three standard
quantizations in the Fock space framework, namely, anti-Wick, Wick and Weyl
quantizations. The first one is a composition of states and is closely related
to the standard scattering identification operator encountered in Quantum
Electrodynamics for time dynamics issues. Anti-Wick quantization and Segal
Bargmann transforms are implied there for that purpose. The other compositions
are for observables (operators in some specific classes) for the Wick and Weyl
symbols. For the Wick symbol of the composition of two operators, we obtain an
absolutely converging series, and for the Weyl symbol, the remainder term of
the asymptotic expansion is absolutely converging, still in the Fock spaces
framework.
