diff --git a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index 6eb74d167..cd7288e8d 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -160,7 +160,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			writeLog("UndefinedPairs; " + undefinedPairs);
 			Set<Set<UnifyPair>> error = new HashSet<>();
 			undefinedPairs = undefinedPairs.stream().map(x -> { x.setUndefinedPair(); return x;}).collect(Collectors.toCollection(HashSet::new));
-			error.add(undefinedPairs);
+			//error.add(undefinedPairs);
 			return error;
 		}
 		
@@ -755,8 +755,9 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				HashMap<PlaceholderType,PlaceholderType> hm = tqp.getInvolvedPlaceholderTypes().stream()
 						.reduce(new HashMap<PlaceholderType,PlaceholderType>(), 
 								(x, y)-> { x.put(y,PlaceholderType.freshPlaceholder()); return x; }, combiner);
-				Optional<Unifier> opt = stdUnify.unify(tqp.accept(new freshPlaceholder(), hm), thetaPrime);
-				if (!opt.isPresent()) {                     //tpq muesse freshtv gesetzt werden PL 2018-03-16
+				Optional<Unifier> opt = stdUnify.unify(
+						tqp.accept(new freshPlaceholder(), hm), thetaPrime);
+				if (!opt.isPresent()) {                     //tqp muesse fresh Typvars gesetzt werden PL 2018-03-16
 					continue;
 				}
 					
diff --git a/src/de/dhbwstuttgart/typeinference/unify/interfaces/UnifyTypeVisitor.java b/src/de/dhbwstuttgart/typeinference/unify/interfaces/UnifyTypeVisitor.java
new file mode 100644
index 000000000..bf435f9ca
--- /dev/null
+++ b/src/de/dhbwstuttgart/typeinference/unify/interfaces/UnifyTypeVisitor.java
@@ -0,0 +1,23 @@
+package de.dhbwstuttgart.typeinference.unify.interfaces;
+
+import java.util.HashMap;
+
+import de.dhbwstuttgart.typeinference.unify.model.ExtendsType;
+import de.dhbwstuttgart.typeinference.unify.model.FunNType;
+import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
+import de.dhbwstuttgart.typeinference.unify.model.ReferenceType;
+import de.dhbwstuttgart.typeinference.unify.model.SuperType;
+
+public interface UnifyTypeVisitor {
+
+	public ReferenceType visit(ReferenceType refty, HashMap<PlaceholderType,PlaceholderType> ht);
+	
+	public PlaceholderType visit(PlaceholderType phty, HashMap<PlaceholderType,PlaceholderType> ht);
+	
+	public FunNType visit(FunNType funnty, HashMap<PlaceholderType,PlaceholderType> ht);
+	
+	public SuperType visit(SuperType suty, HashMap<PlaceholderType,PlaceholderType> ht);
+	
+	public ExtendsType visit(ExtendsType extty, HashMap<PlaceholderType,PlaceholderType> ht);
+
+}
diff --git a/test/javFiles/Matrix.jav b/test/javFiles/Matrix.jav
index a680370f4..ec3fdb93a 100644
--- a/test/javFiles/Matrix.jav
+++ b/test/javFiles/Matrix.jav
@@ -17,7 +17,7 @@ class Matrix extends Vector<Vector<Integer>> {
                 var k = 0;
                 while(k < v1.size()) {
                 		//erg = erg + v1.elementAt(k) * m.elementAt(k).elementAt(j);
-                    erg = add1(erg, mul1(v1.elementAt(k),
+                    erg = add(erg, mul1(v1.elementAt(k),
                              m.elementAt(k).elementAt(j)));
                     k++; }
                 v2.addElement(new Integer(erg));