Package org.tweetyproject.arg.delp.syntax

Class DefeasibleLogicProgram

java.lang.Object

org.tweetyproject.commons.BeliefSet<DelpRule,FolSignature>

org.tweetyproject.arg.delp.syntax.DefeasibleLogicProgram

All Implemented Interfaces:

Iterable<DelpRule>, Collection<DelpRule>, BeliefBase

public class DefeasibleLogicProgram
extends BeliefSet<DelpRule,FolSignature>

This class models a defeasible logic program (DeLP).

Author:

Matthias Thimm

Field Summary

Fields inherited from class org.tweetyproject.commons.BeliefSet

EQUALS_USES_SIGNATURE

Constructor Summary

Constructors

Constructor	Description
DefeasibleLogicProgram()	Default constructor; initializes empty delpFacts, strict and defeasible rules and empty comparison criterion.
DefeasibleLogicProgram(DefeasibleLogicProgram delp)	constructor; initializes this program with the given program

Method Summary

Modifier and Type	Method	Description
boolean	disagree(Set<FolFormula> literals)	Checks whether the given set of literals disagree with respect to the strict part of this program.
Set<DelpArgument>	getArguments()	Returns the set of all possible arguments, that can be built in this delp.
DungTheory	getDungTheory()	This method translates this delp into an abstract Dung theory.
Signature	getMinimalSignature()	Returns the signature of the language of this knowledge base.
Set<DelpRule>	getRulesWithHead(FolFormula l)	Returns all defeasible and strict rules appearing in this program with the given literal as head
Set<FolFormula>	getStrictClosure()	Computes the strict closure of the program, i.e., the set of all strictly derivable literals.
Set<FolFormula>	getStrictClosure(Set<FolFormula> literals)	Computes the strict closure of the program, i.e., the set of all strictly derivable literals.
Set<FolFormula>	getStrictClosure(Set<FolFormula> literals, Set<DefeasibleRule> defeasibleRules)	Computes the strict closure of the program, i.e., the set of all strictly derivable literals.
Set<FolFormula>	getStrictClosure(Set<FolFormula> literals, Set<DefeasibleRule> defeasibleRules, boolean usefacts)	Computes the strict closure of the program, i.e., the set of all strictly derivable literals.
DefeasibleLogicProgram	ground()	In general, a delp comprises of rule schemes with variables.
DefeasibleLogicProgram	ground(Set<Constant> constants)	In general, a delp comprises of rule schemes with variables.
boolean	isConsistent(Set<DefeasibleRule> rules)	Checks whether the given set of defeasible rules are consistent given the strict part of this program.
boolean	isGround()	Checks if all the rules in the current collection are grounded.
static void	main(String[] args)	Parsing DeLP from given file and performing given query against it.
String	toString()	Returns a string representation of the collection of rules.

Methods inherited from class org.tweetyproject.commons.BeliefSet

add, add, addAll, clear, contains, containsAll, equals, getSignature, hashCode, isEmpty, iterator, remove, removeAll, retainAll, setSignature, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

parallelStream, removeIf, spliterator, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Constructor Details

DefeasibleLogicProgram

public DefeasibleLogicProgram()

Default constructor; initializes empty delpFacts, strict and defeasible rules and empty comparison criterion.

DefeasibleLogicProgram

public DefeasibleLogicProgram(DefeasibleLogicProgram delp)

constructor; initializes this program with the given program

Parameters:

delp - a defeasible logic program

Method Details

ground

public DefeasibleLogicProgram ground()

In general, a delp comprises of rule schemes with variables. This methods returns the corresponding grounded theory, i.e., all schematic elements are replaced with all their grounded instances, where all occurring variables are replaced with constants in every possible way. The set of constants used is the set of constants appearing in this delp.

Returns:

the grounded version of this

ground

public DefeasibleLogicProgram ground(Set<Constant> constants)

In general, a delp comprises of rule schemes with variables. This methods returns the corresponding grounded theory, i.e., all schematic elements are replaced with all their grounded instances, where all occurring variables are replaced with constants in every possible way.

Parameters:

constants - some set of constants.

Returns:

the grounded version of this

getDungTheory

public DungTheory getDungTheory()

This method translates this delp into an abstract Dung theory. All arguments, that can be built in this theory are interpreted as abstract arguments. The attack relation is built using the dialectical proof theory of delp.

Returns:

the abstract Dung theory induced by this delp.

getArguments

public Set<DelpArgument> getArguments()

Returns the set of all possible arguments, that can be built in this delp.

Returns:

the set of all possible arguments, that can be built in this delp.

getStrictClosure

public Set<FolFormula> getStrictClosure(Set<FolFormula> literals,
 Set<DefeasibleRule> defeasibleRules,
 boolean usefacts)

Computes the strict closure of the program, i.e., the set of all strictly derivable literals. For this computation the program may be extended by the given parameters

Parameters:

literals - a set of literals

defeasibleRules - a set of defeasible rules

usefacts - set to true iff the delpFacts of this program shall be used in computing the closure

Returns:

the closure of this program and the given parameters

getStrictClosure

public Set<FolFormula> getStrictClosure(Set<FolFormula> literals,
 Set<DefeasibleRule> defeasibleRules)

Computes the strict closure of the program, i.e., the set of all strictly derivable literals. The program is extended with delpFacts and defeasible rules (which are interpreted as strict rules here) described by the parameters literals and defeasibleRules.

Parameters:

literals - a set of literals

defeasibleRules - a set of defeasible rules

Returns:

the set of all strictly derivable literals.

getStrictClosure

public Set<FolFormula> getStrictClosure(Set<FolFormula> literals)

Computes the strict closure of the program, i.e., the set of all strictly derivable literals. The program is extended with delpFacts described by the parameter literals

Parameters:

literals - a set of literals

Returns:

the set of all strictly derivable literals.

getStrictClosure

public Set<FolFormula> getStrictClosure()

Computes the strict closure of the program, i.e., the set of all strictly derivable literals.

Returns:

the set of all strictly derivable literals.

isConsistent

public boolean isConsistent(Set<DefeasibleRule> rules)

Checks whether the given set of defeasible rules are consistent given the strict part of this program.

Parameters:

rules - a set of defeasible rules

Returns:

false if the union of this program's delpFacts and strict rules with the given set of defeasible rules defeasibly derives two complementary literals

disagree

public boolean disagree(Set<FolFormula> literals)

Checks whether the given set of literals disagree with respect to the strict part of this program.

Parameters:

literals - a set of literals

Returns:

true if the union of this program's delpFacts and strict rules with the given set of literals defeasibly derives two complementary literals

isGround

public boolean isGround()

Checks if all the rules in the current collection are grounded.

A rule is considered grounded if it has no uninstantiated variables, meaning that all its variables have been assigned concrete values. This method verifies this condition for all the rules in the collection.

Returns:

true if all rules in the collection are grounded; false otherwise.

toString

public String toString()

Returns a string representation of the collection of rules.

This method converts each rule in the collection to its string representation and concatenates them, separated by newline characters. The final result is a single string where each rule is displayed on a new line.

Specified by:

toString in interface BeliefBase

Overrides:

toString in class BeliefSet<DelpRule,FolSignature>

Returns:

A string representation of the collection of rules, with each rule on a new line.

getRulesWithHead

public Set<DelpRule> getRulesWithHead(FolFormula l)

Returns all defeasible and strict rules appearing in this program with the given literal as head

Parameters:

l - a literal

Returns:

a set of strict and defeasible rules

getMinimalSignature

public Signature getMinimalSignature()

Description copied from interface: BeliefBase

Returns the signature of the language of this knowledge base.

Returns:

the signature of the language of this knowledge base.

main

public static void main(String[] args)
                 throws IOException,
org.kohsuke.args4j.CmdLineException

Parsing DeLP from given file and performing given query against it.

Parameters:

args - Options and arguments (try "-h" to get a help text with details)

Throws:

IOException - if an IO issue occurs.

org.kohsuke.args4j.CmdLineException - if there is some problem parsing the command line