LPForget:

A System of Forgetting in Answer Set Programming

Fu-Leung Cheng1 Thomas Eiter2 Nathan Robinson1 Abdul Sattar1 Kewen Wang1
1Griffith University, Australia
2Technische Universität Wien, Austria


System use instructions

  • The system should first be downloaded from the download page.
  • It can then be run by executing lpforget.jar.
  • The system has two major components: the forgetting system and the conflict resolution system each which can be accessed from the main application screen.
  • The forgetting system:
    • Programs can either be manually entered in the left hand text area or loaded from a set of predefined examples through the open file button in the menu bar.
    • Example files for the forgetting system are contained in the following folder clientRoot\Examples\Forget\.
    • Once an example has been entered or loaded the literal to be forgotten should be entered in the indicated text box.
    • The required forgetting algorithm can then be selected and the result of forgetting calculated and displayed by pressing the Compute button.
    • The forgetting system can be closed through the file menu or the standard window closing method which will take the user back to the main application screen.
  • The conflict resolution system:
    • The conflict resolution system provides a means to have multiple agents with preferences or requirements and also a set of general constraints or rules.
    • It is recommended that the user load several examples to get a feel for the system which are contained in the following folder clientRoot\Examples\CRS\.
    • To manually enter a problem the following steps should be taken:
      • Select the Constraints tab and enter the required constraints and rules.
      • Add the required number of agents by repeatedly pressing the Add Agents button and then add the required rules for each agent by selecting its tab and entering the rules into the displayed text area.
    • Press the Compute Agreements button to check if the constraints and agents preferences are jointly consistent.
    • If they are consistent then the answer sets which compose the solution will be displayed in the Solution tab.
    • If they are inconsistent then a message will appear in the Solution tab indicating so and the Enter Compromise button should be pressed which will create tabs to allow the user to select the compromise that each agent will make.
    • The Compromise Suggestions button will display a window with some suggestions for what literals can be forgotten so that a compromise can be reached.
    • Once the literals to forget have been selected for each agent the Apply Forgetting button will forget the selected literals. If a compromise has been reached it will display the solution otherwise it will indicate that further literals will need to be forgotten for a compromise to be reached.
    • The problem can be cleared by clicking the restart button.

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