Model-100: Specification language for interacting processes

Basic ideas and constructs of the Model-100 language designed for describing behavior of interacting processes are discussed. Process interaction rules are specified by clauses of the form “if … then …” (Horn clauses). Structure of the interactions is presented by a graph described by a rational term. Execution of one step of the program reduces to simultaneous application of all rules to all nodes to which the rule can be applied (i.e., to all rational subterms with which the Horn clause can be unified).