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Domain schemata

The domain model of P&R contains the following types of information

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• Attribute, solution value range constraint pairs.

• Attribute, proposed value algorithm (procedure) pairs.

• Constraint violation, revision pairs.

The following domain schemata are used:

1. constraint-op(+A:attribute, -C:constraint*)

   Returns a list of constraints on the value of the attribute. These constraints can either be absolute or in terms of the values of other attributes.

2. propose-op(+A:attribute, -V:value*)

   Returns a value (or a list if the attribute is multidimensional) for the attribute. The value is either absolute or in terms of the values of other attributes.

3. revise-op(+A:attribute, +V:value*, +C:constraint, -R:revision)

   Returns a list of revisions values (or list of values) with associated preferences for an attribute that violates with value constraint . Revisions are not necessarily specific for every value.

4. preference-op(+R:revision*, -P:preference*)

   Returns a preference list of the revision. In the original SALT approach this information was acquired from the user.

5. antagonistic-op(+C:constraint, -S:constraint*)

   Returns a set of antagonistic constraints referring to constraint . This means that these constraints should be treated as a set. Antagonistic constraints are all re-checked when a revision is applied to one of the elements of the set.