Entanglement and quantum logical gates. Part I

Is it possible to give a logical characterization of entanglement and of entanglementmeasures in terms of the probabilistic behavior of some gates? This question admits different (positive or negative) answers in the case of different systems of gates and in the case of different classes of density operators. In the first part of this article we investigate possible relations between entanglement-measures and the probabilistic behavior of quantum computational conjunctions