Package edu.uky.ai.logic

Class Negation

java.lang.Object
edu.uky.ai.logic.BooleanProposition
edu.uky.ai.logic.Negation
All Implemented Interfaces:
Formula, Proposition, Comparable<Formula>
Direct Known Subclasses:
NegatedAtom
public class Negation extends BooleanProposition
Represents the negation (or opposite) of a proposition. A negation is true just when it argument is false, and false just when its argument is true.
Author:
Stephen G. Ware

  • Field Details

    • NEGATION_PREDICATE

      public static final String NEGATION_PREDICATE
      The word used to express a negation
      See Also:

    • argument

      public final Proposition argument
      The proposition this formula is the opposite of

  • Constructor Details

    • Negation

      public Negation(Proposition argument)
      Constructs a new negation with the given proposition.
      Parameters:
      argument - the proposition this formula will be the opposite of

  • Method Details

    • equals

      public boolean equals(Object other)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • substitute

      public Proposition substitute(Substitution substitution)
      Description copied from interface: Formula
      Returns a version of this formula such that any elements that appear in the given substitution are replaced.
      Parameters:
      substitution - the substitution
      Returns:
      a formula with replacements from the substitution

    • unify

      public Bindings unify(Formula other, Bindings bindings)
      Description copied from interface: Formula
      Finds the bindings that would be necessary to make this formula the same as another formula (if any exist).
      Parameters:
      other - the other formula
      bindings - an existing set of bindings that will be added to
      Returns:
      the bindings that would make both formulas the same, or null if so such bindings exist

    • isTrue

      public boolean isTrue(State state)
      Description copied from interface: Proposition
      Tests whether this proposition is true in the given state.
      Parameters:
      state - the state in which to test this proposition
      Returns:
      true if the proposition is true, false otherwise

    • makeTrue

      public void makeTrue(MutableState state)
      Description copied from interface: Proposition
      Modifies the given state object to make this proposition true. Note that some propositions (such as Disjunctions) are non-deterministic, meaning there are multiple ways to make them true, and thus the state that would result from this operation is not clearly defined.
      Parameters:
      state - the state to modify

    • simplify

      public Proposition simplify()
      Description copied from interface: Proposition
      Returns an equivalent proposition which may be simpler.
      Returns:
      the simplified proposition

    • negate

      public Proposition negate()
      Description copied from interface: Proposition
      Returns a proposition whose truth values are opposite of this proposition (i.e. true when this one is false, false when this one is true).
      Returns:
      a proposition with opposite truth values

    • toCNF

      public Proposition toCNF()
      Description copied from interface: Proposition
      Converts this proposition to Conjunctive Normal Form (CNF). There are three kinds of formulas that are considered to be in CNF:
      1. A Literal by itself
      2. A Disjunction of literals, called a clause
      3. A Conjunction of clauses
      Returns:
      an equivalent proposition in CNF

    • toDNF

      public Proposition toDNF()
      Description copied from interface: Proposition
      Converts this proposition to Disjunctive Normal Form (DNF). There are three kinds of formulas that are considered to be in DNF:
      1. A Literal by itself
      2. A Conjunction of literals, called a clause
      3. A Disjunction of clauses
      Returns:
      an equivalent proposition in DNF