Within a general operational framework I show that a-causality at a distance
of "local actions" (the so-called "no-signaling") is a direct consequence of
commutativity of local transformations, i.e. of dynamical independence. On the
other hand, the tensor product of Quantum Mechanics is not just a consequence
of such dynamical independence, but needs in addition the Local Observability
Principle.Comment: Presented at the conference "Theory and Technology in Quantum
Information, Communication, Computation and Cryptography", Trieste SISSA,
June 2006. Submitted to J. Phys. A. Math. Ge
