Logic programming with constraints

• Author / Creator

  Liu, Guohua

• Answer set programming (ASP), namely logic programming under the answer set semantics, provides a promising constraint programming paradigm, due to its simple syntax, high expressiveness, and effective computational properties. This programming paradigm can be viewed as a variant of SAT. A main drawback of ASP, like SAT, is that the framework is primarily formulated for reasoning with individuals, where each is represented by an atom in the traditional sense. Recently, ASP has been extended to include constraints to facilitate reasoning with sets of atoms in an explicit manner. These constraints include weight constraints, aggregates, and abstract constraints. Logic programs with these constraints are referred to as weight constraint, aggregate and abstract constraint programs.

  We investigate the properties and computations of weight constraint, aggregate, and abstract constraint programs, respectively. For properties, we improve the formulation of loop formulas for weight constraint and aggregate programs, propose loop formulas for abstract constraint programs, and characterize strong equivalence of these programs. For computations, we refine the existing constraint propagation mechanism in the computation of weight constraint programs and advocate a new approach to computing aggregate programs.

• Subjects / Keywords

  • Constraint programming (Computer science)
  • Logic programming

• Graduation date

  Spring 2010

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R37K5S

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.