This sub-domain represents the current state of all nodes which belong to network. The atomic part of this sub-domain is the State. A State is an entity characterized by an identificator, which is a reference to the related Node, a value, which represents the boolean value of the State. State and Node concepts have to be separated because definition of Node is related only to the structure of the network while the State exploits the Node identificator to represent Node value at a fixed instant. In order to the describing the entire BN state at a xed instant, it has to be developed also a State aggregator called States. In this entity, all the operator which manipulates State are inserted and all the operator that let a developer creates a custom States of the BN or a randomically generated one. For this reason, I have to outline that State and Node need to have the same identi cator. During implementation phase, a validation check in order to avoid potential error will be inserted. During the updating of the BN, the States will create a Trajectory of the BN, which will begin with a Transient and will finish in an Attractor. Transient and Attractor have to be defined as aggregator of States. In fact, States entity represents the value of all Node of the BN at a xed time t. If States are aggregated, it is possible to collect States succession during the evolution of the BN. Trajectory entity will encapsulate the Transient and Attractor starting from an initial state.