 The models of FOPL are of the form \(M = (W,D,I,P)\), where \(W\) is a set of possible worlds, \(D\) is a domain of discourse, \(I\) is a localized interpretation function mapping every \(w\in W\) to a interpretation function \(I(w)\) that associates to every function and predicate symbol, a function or predicate of appropriate arity, and \(P\) is a probability function that assign a probability \(P(w)\) to every \(w\) in \(W\).