Package org.tweetyproject.arg.adf.syntax.pl

Interface Literal

public interface Literal

The Literal interface represents a logical literal, which can be either a positive or negative proposition. Literals are fundamental components in propositional logic and SAT solvers. They can be used to construct clauses, represent assumptions, and encode constraints.

Author:

Mathias Hofer

Method Summary

Modifier and Type	Method	Description
static Literal	create()	Creates a new unnamed atom literal.
static Literal	create(String name)	Creates a new named atom literal with the specified name.
static Literal	createTransient()	Creates a new transient atom literal.
Literal	getAtom()	Retrieves the atom of this literal.
String	getName()	Returns the name of this literal.
boolean	isPositive()	Checks if this literal is positive.
boolean	isTransient()	Checks if this literal is transient.
Literal	neg()	Returns the negation of this literal.

Method Details

isTransient

boolean isTransient()

Checks if this literal is transient. Transient literals are usually temporary and are not used as permanent identifiers.

Returns:

true if the literal is transient, false otherwise

isPositive

boolean isPositive()

Checks if this literal is positive. A positive literal represents a proposition in its original form, whereas a negative literal represents the negation of a proposition.

Returns:

true if the literal is positive, false if it is negative

getAtom

Literal getAtom()

Retrieves the atom of this literal. If the literal is a negation, this method returns the encapsulated atom. If the literal is an atom, it returns itself.

Returns:

the atom of the literal, or this literal if it is an atom

getName

String getName()

Returns the name of this literal. The name may be null if the literal does not have a specific name (e.g., in the case of transient literals).

Returns:

the name of the literal, or null if it does not have a name

neg

Literal neg()

Returns the negation of this literal. The following properties hold for every literal l:

• l.neg().neg() == l: The negation of the negation returns the original literal.
• l.neg().getAtom() == l.getAtom(): The negation of the literal has the same atom.

The following property might not hold for every literal l:

• l.neg() == l.neg(): The negation of a literal might not be equal to itself.

Returns:

the negation of this literal

create

static Literal create()

Creates a new unnamed atom literal. This is a default literal without any specific name.

Returns:

a new unnamed atom literal

create

static Literal create(String name)

Creates a new named atom literal with the specified name. If the provided name is null, an unnamed atom literal is created instead.

Parameters:

name - the name of the literal, or null for an unnamed literal

Returns:

a new named atom literal, or an unnamed atom literal if the name is null

createTransient

static Literal createTransient()

Creates a new transient atom literal. Transient literals are typically used for temporary or intermediate purposes and do not have a permanent name.

Returns:

a new transient atom literal