Enumeration specifying the different types of Compound Condition Opaque Statement is a concrete Statement that uses OpaqueExpression attributes (language and body) to store its expression as a string. Boolean ValueSpecification is a kind of ValueSpecification that specifies a boolean value. Statement is a Boolean ValueSpecification that does not constrain anything. Statements are used to integrate with rule models. An Opaque Condition is a Condition that can be expressed in free text. A Condition is a Boolean ValueSpecification that constrains some element in the models. Conditions are true if their descriptions hold in the current state of the world, possibly including executions, and false otherwise. A Fact Condition is a Condition that is true when the two ValueSpecifications to which they refer yield equal values, and false otherwise. A Compound Condition is a kind of Condition that is the combination of other Conditions. There are three kinds of Compound Condition:. . or : the Compound Condition is the result of one the combined condition . and: the Compound Condition is the result of all the combined condition . not: the Compound Condition is result of the negation of all the combined condition .