Lparse 1.0 User's Manual - ASP and Smodels

Answer Set Programming (ASP) is a programming paradigm in which the programmer describes the problem using a formal language and an underlying engine finds a solution to the problem.

Smodels is a system for ASP. Smodels programs are written using standard logic programming notation. The programs are composed of atoms and inference rules. Programs represent problems, an answer to a problem is a set of atoms, called stable model, that tell which atoms are true. A Smodel program may have none, one or many stable models. The stable models may be seen as a set of rational beliefs about the program. Smodels program example:

ide_drive       :- hard_drive, not scsi_drive.
scsi_drive      :- hard_drive, not ide_drive.
scsi_controller :- scsi_drive.
hard_drive 

This program has two stable models:

M1 = { hard_drive, ide_drive }

And

M2 = { hard_drive, scsi_drive, scsi_controller }

Smodels is implemented by Patrick Simons. The above information comes from this website: Computing the Stable model semantics and their user manual