Assertions Constraints All possible types of constraints in situation theory can be classified as either conditional or unconditional . Conditional constraints can be applied to situations that satisfy some condition while unconditional constraints can be applied to all situations. Variables in BABY-SIT are only used in constraints and query expressions, and have scope only within the constraint or the query expression they appear. Each constraint has an identifier associated with it and must belong to a group of constraints. G are variables.
G can have values of some type appropriate for the argument roles of loads and loaded .
This constraint can apply in any situation. Hence, BABY-SIT constraints can be global. Constraints can also be situated. Background conditions are accepted to be true by default, unless stated otherwise. Background conditions are, in fact, assumptions which are required to hold for constraints to be eligible for activation.