Tabling with Answer Subsumption: Implementation, Applications and Performance

Tabled Logic Programming (TLP) is becoming widely available in Prolog systems, but most implementations of TLP implement only answer variance in which an answer A is added to the table for a subgoal S only if A is not a variant of any other answer already in the table for S. While TLP with answer variance is powerful enough to implement the well-founded semantics with good termination and complexity properties, TLP becomes much more powerful if a mechanism called answer subsumption is used. XSB implements two forms of answer subsumption. The first, partial order answer subsumption, adds A to a table only if A is greater than all other answers already in the table according to a user-defined partial order. The second, lattice answer subsumption, may join A to some other answer in the table according to a user-defined upper semi-lattice. Answer subsumption can be used to implement paraconsistent and quantitative abstract analysis domains, and preference logics. This paper discusses the s...

• Type: Journal
• Year: 2010
• Where: JELIA
• Authors: Terrance Swift, David Scott Warren
• Keywords: Answer Subsumption, Artificial Intelligence, JELIA 2010, Lattice Answer Subsumption, Partial Order