diff --git a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index cae65fae..6eb74d16 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -3,6 +3,7 @@ package de.dhbwstuttgart.typeinference.unify;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
@@ -11,6 +12,7 @@ import java.util.Map.Entry;
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.RecursiveTask;
+import java.util.function.BinaryOperator;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -749,7 +751,11 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				//System.out.println(i);
 				//if (i == 62)
 				//	System.out.println(tqp.toString());
-				Optional<Unifier> opt = stdUnify.unify(tqp.setTypeParams(newTp), thetaPrime);
+				BinaryOperator<HashMap<PlaceholderType,PlaceholderType>> combiner = (x,y) -> { x.putAll(y); return x;};
+				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
 					continue;
 				}
diff --git a/src/de/dhbwstuttgart/typeinference/unify/freshPlaceholder.java b/src/de/dhbwstuttgart/typeinference/unify/freshPlaceholder.java
new file mode 100644
index 00000000..45ccb6bb
--- /dev/null
+++ b/src/de/dhbwstuttgart/typeinference/unify/freshPlaceholder.java
@@ -0,0 +1,47 @@
+package de.dhbwstuttgart.typeinference.unify;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.HashMap;
+import java.util.stream.Collectors;
+
+import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
+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;
+import de.dhbwstuttgart.typeinference.unify.model.TypeParams;
+
+public class freshPlaceholder implements UnifyTypeVisitor {
+
+	public ReferenceType visit(ReferenceType refty, HashMap<PlaceholderType,PlaceholderType> ht) {
+		return new ReferenceType(refty.getName(),
+				new TypeParams(
+						Arrays.stream(refty.getTypeParams().get())
+						.map(x -> x.accept(this, ht))
+						.collect(Collectors.toCollection(ArrayList::new))));
+	}
+	
+	public PlaceholderType visit(PlaceholderType phty, HashMap<PlaceholderType,PlaceholderType> ht) {
+		return ht.get(phty);
+	}
+	
+	public FunNType visit(FunNType funnty, HashMap<PlaceholderType,PlaceholderType> ht) {
+		return FunNType.getFunNType(
+				new TypeParams(
+						Arrays.stream(funnty.getTypeParams().get())
+						.map(x -> x.accept(this, ht))
+						.collect(Collectors.toCollection(ArrayList::new)))
+				);	
+	}
+	
+	public SuperType visit(SuperType suty, HashMap<PlaceholderType,PlaceholderType> ht) {
+		return new SuperType(suty.getWildcardedType().accept(this, ht));
+	}
+	
+	public ExtendsType visit(ExtendsType extty, HashMap<PlaceholderType,PlaceholderType> ht) {
+		return new ExtendsType(extty.getWildcardedType().accept(this, ht));
+	}
+}
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java b/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java
index 510e4162..a97977c5 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java
@@ -2,7 +2,7 @@ package de.dhbwstuttgart.typeinference.unify.model;
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -13,7 +13,7 @@ import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
  */
 public final class ExtendsType extends WildcardType {
 	
-	public UnifyType accept(UnifyTypeVisitor visitor, Hashtable<PlaceholderType,PlaceholderType> ht) {
+	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java b/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
index 44a4fa71..dd96dedd 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
@@ -1,6 +1,6 @@
 package de.dhbwstuttgart.typeinference.unify.model;
 
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -12,7 +12,7 @@ import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
  */
 public class FunNType extends UnifyType {
 
-	public UnifyType accept(UnifyTypeVisitor visitor, Hashtable<PlaceholderType,PlaceholderType> ht) {
+	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java b/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
index a85f356f..5aab8784 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
@@ -2,8 +2,8 @@ package de.dhbwstuttgart.typeinference.unify.model;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Hashtable;
 import java.util.Random;
 import java.util.Set;
 
@@ -56,7 +56,7 @@ public final class PlaceholderType extends UnifyType{
 		IsGenerated = isGenerated;
 	}
 	
-	public UnifyType accept(UnifyTypeVisitor visitor, Hashtable<PlaceholderType,PlaceholderType> ht) {
+	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java b/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
index f1023862..133a87ed 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
@@ -1,6 +1,6 @@
 package de.dhbwstuttgart.typeinference.unify.model;
 
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -19,7 +19,7 @@ public final class ReferenceType extends UnifyType {
 	private final int hashCode;
 	
 
-	public UnifyType accept(UnifyTypeVisitor visitor, Hashtable<PlaceholderType,PlaceholderType> ht) {
+	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java b/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java
index c746bd47..0b98c159 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java
@@ -1,6 +1,6 @@
 package de.dhbwstuttgart.typeinference.unify.model;
 
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -12,7 +12,7 @@ import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
  */
 public final class SuperType extends WildcardType {
 	
-	public UnifyType accept(UnifyTypeVisitor visitor, Hashtable<PlaceholderType,PlaceholderType> ht) {
+	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java b/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java
index 66bd80a8..16986d65 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java
@@ -2,7 +2,7 @@ package de.dhbwstuttgart.typeinference.unify.model;
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Set;
 
@@ -37,7 +37,7 @@ public abstract class UnifyType {
 	}
 	
 
-	abstract public UnifyType accept(UnifyTypeVisitor visitor, Hashtable<PlaceholderType,PlaceholderType> ht); 
+	abstract public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht); 
 	
 	/**
 	 * Returns the name of the type.