bugfix pl model computation

Author: larsbengel

org-tweetyproject-logics-pl/src/main/java/org/tweetyproject/logics/pl/syntax/Equivalence.java

@@ -30,6 +30,7 @@
  * This class models equivalence of propositional logic.
  * 
  * @author Anna Gessler
+ * @author Lars Bengel
  */
 public class Equivalence extends PlFormula {
 
@@ -138,7 +139,7 @@ public Conjunction toCnf() {
 	public Set<PossibleWorld> getModels(PlSignature sig) {
 		Disjunction d1 = new Disjunction(new Negation(this.formulas.getFirst()),this.formulas.getSecond());
 		Disjunction d2 = new Disjunction(new Negation(this.formulas.getSecond()),this.formulas.getFirst()); 
-		return (new Conjunction(d1,d2)).getModels();
+		return (new Conjunction(d1,d2)).getModels(sig);
 	}
 
 	@Override

org-tweetyproject-logics-pl/src/main/java/org/tweetyproject/logics/pl/syntax/ExclusiveDisjunction.java

@@ -30,6 +30,7 @@
  * 
  * @author Anna Gessler
  * @author Matthias Thimm
+ * @author Lars Bengel
  */
 public class ExclusiveDisjunction extends AssociativePlFormula {
 
@@ -172,7 +173,7 @@ public PlFormula trim() {
 	@Override
 	public Set<PossibleWorld> getModels(PlSignature sig) {
 		Conjunction cnf = this.toCnf();
-		return cnf.getModels();
+		return cnf.getModels(sig);
 	}
 
 	/*

org-tweetyproject-logics-pl/src/main/java/org/tweetyproject/logics/pl/syntax/Implication.java

@@ -30,6 +30,7 @@
  * This class models the implication of propositional logic.
  * 
  * @author Anna Gessler
+ * @author Lars Bengel
  */
 public class Implication extends PlFormula {
 
@@ -181,7 +182,7 @@ public Conjunction toCnf() {
 	@Override
 	public Set<PossibleWorld> getModels(PlSignature sig) {
 		Disjunction d = new Disjunction(new Negation(this.formulas.getFirst()), this.formulas.getSecond()); // (A=>B)
-		return d.getModels();
+		return d.getModels(sig);
 	}
 
 	@Override