Package edu.uky.ai.logic

Class Implication

java.lang.Object
edu.uky.ai.logic.BooleanProposition
edu.uky.ai.logic.Implication
All Implemented Interfaces:
Formula, Proposition, Comparable<Formula>
public class Implication extends BooleanProposition
An implication, or logical IF statement, is defined by the truth value of its two parts, the antecedent and the consequent. It is always true, except when the antecedent is true and the consequent is false.
Author:
Stephen G. Ware

  • Field Details

    • IMPLICATION_PREDICATE

      public static final String IMPLICATION_PREDICATE
      The word used to express an implication
      See Also:

    • antecedent

      public final Proposition antecedent
      The first part of the implication

    • consequent

      public final Proposition consequent
      The second part of the implication, which is implied by the antecedent

  • Constructor Details

    • Implication

      public Implication(Proposition antecedent, Proposition consequent)
      Constructs an implication from a given antecedent and consequent.
      Parameters:
      antecedent - the first part of the implication
      consequent - the second part of the implication which is implied by the antecedent

  • 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