diff --git a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index 626ec74e..0ac9fe63 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -898,7 +898,10 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				unifier.swapPlaceholderSubstitutions(thetaPrime.getTypeParams());
 				Set<UnifyPair> substitutionSet = new HashSet<>();
 				for (Entry<PlaceholderType, UnifyType> sigma : unifier) {
-					substitutionSet.add(new UnifyPair(sigma.getKey(), sigma.getValue(), PairOperator.EQUALSDOT, pair.getSubstitution(), pair));
+					substitutionSet.add(new UnifyPair(sigma.getKey(), sigma.getValue(), PairOperator.EQUALSDOT, 
+							//TODO: nochmals ueberlegen ob hier pair.getSubstitution() korrekt ist, oder ob leere Menge hin müsste
+							//alle folgenden New UnifyPair ebenfalls ueberpruefen PL 2018-04-19
+							pair.getSubstitution(), pair));
 				}
 				//List<UnifyType> freshTphs = new ArrayList<>(); PL 18-02-06 in die For-Schleife verschoben
 				for (UnifyType tq : thetaQs) {
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java b/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
index 4aa4ffb8..b45309b8 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
@@ -453,7 +453,8 @@ public class FiniteClosure extends Ordering<UnifyType> implements IFiniteClosure
 		HashSet<UnifyPair> hs = new HashSet<>();
 		hs.add(up);
 		Set<UnifyPair> smallerRes = unifyTask.applyTypeUnificationRules(hs, this);
-		long smallerLen = smallerRes.stream().filter(x -> !(x.getLhsType() instanceof PlaceholderType && x.getRhsType() instanceof PlaceholderType)).count();
+		//Gleichungen der Form a <./=. Theta oder Theta <./=. a oder a <./=. b sind ok. 
+		long smallerLen = smallerRes.stream().filter(x -> !(x.getLhsType() instanceof PlaceholderType || x.getRhsType() instanceof PlaceholderType)).count();
 		if (smallerLen == 0) return -1;
 		else {
 			up = new UnifyPair(right, left, pairop);
@@ -461,7 +462,8 @@ public class FiniteClosure extends Ordering<UnifyType> implements IFiniteClosure
 			hs = new HashSet<>();
 			hs.add(up);
 			Set<UnifyPair> greaterRes = unifyTask.applyTypeUnificationRules(hs, this);
-			long greaterLen = greaterRes.stream().filter(x -> !(x.getLhsType() instanceof PlaceholderType && x.getRhsType() instanceof PlaceholderType)).count();
+			//Gleichungen der Form a <./=. Theta oder Theta <./=. a oder a <./=. b sind ok. 
+			long greaterLen = greaterRes.stream().filter(x -> !(x.getLhsType() instanceof PlaceholderType || x.getRhsType() instanceof PlaceholderType)).count();
 			if (greaterLen == 0) return 1;
 			else return 0;
 		}	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/OrderingUnifyPair.java b/src/de/dhbwstuttgart/typeinference/unify/model/OrderingUnifyPair.java
index ee78d6fa..9d948cdc 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/OrderingUnifyPair.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/OrderingUnifyPair.java
@@ -132,9 +132,13 @@ public class OrderingUnifyPair extends Ordering<Set<UnifyPair>> {
 			else return si.get();
 		}
 		//Fall 1 und 4
-		if (lefteq.size() == 1 && righteq.size() == 1 && (leftlewc.size() > 0 || rightlewc.size() > 0)) {
-			if (lefteq.iterator().next().getLhsType().getName().equals("A")) 
+		if (lefteq.size() >= 1 && righteq.size() >= 1 && (leftlewc.size() > 0 || rightlewc.size() > 0)) {
+			if (lefteq.iterator().next().getLhsType().getName().equals("D")) 
 				System.out.print("");
+			Set<PlaceholderType> varsleft = lefteq.stream().map(x -> (PlaceholderType)x.getLhsType()).collect(Collectors.toCollection(HashSet::new));
+			Set<PlaceholderType> varsright = righteq.stream().map(x -> (PlaceholderType)x.getLhsType()).collect(Collectors.toCollection(HashSet::new));
+			lefteq.removeIf(x -> !varsright.contains(x.getLhsType()));
+			righteq.removeIf(x -> !varsleft.contains(x.getLhsType()));
 			UnifyPair lseq = lefteq.iterator().next();
 			UnifyPair rseq = righteq.iterator().next();
 			if (lseq.getRhsType().getName().equals("Object")) {
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/Unifier.java b/src/de/dhbwstuttgart/typeinference/unify/model/Unifier.java
index dfb88bc7..f0f8164c 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/Unifier.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/Unifier.java
@@ -72,11 +72,26 @@ public class Unifier implements Function<UnifyType, UnifyType>, Iterable<Entry<P
 	
 	/**
 	 * Applies the unifier to the two terms of the pair.
+	 * works only for single subsitution
 	 * @return A new pair where the left and right-hand side are applied
 	 */
 	public UnifyPair apply(UnifyPair thisAsPair, UnifyPair p) {
 		UnifyType newLhs = this.apply(p.getLhsType());
 		UnifyType newRhs = this.apply(p.getRhsType());
+		//Varianceweitergabe
+		PlaceholderType lhsph = (PlaceholderType)thisAsPair.getLhsType();
+		if (lhsph.getVariance() != 0) {
+			if (p.getLhsType().equals(lhsph)) {
+				if (p.getRhsType() instanceof PlaceholderType) {
+					((PlaceholderType)p.getRhsType()).setVariance(lhsph.getVariance());
+				}
+			}
+			if (p.getRhsType().equals(lhsph)) {
+				if (p.getLhsType() instanceof PlaceholderType) {
+					((PlaceholderType)p.getLhsType()).setVariance(lhsph.getVariance());
+				}
+			}
+		}
 		if (!(p.getLhsType().equals(newLhs)) || !(p.getRhsType().equals(newRhs))) {//Die Anwendung von this hat was veraendert PL 2018-04-01
 			Set<UnifyPair> suniUnifyPair = new HashSet<>();
 			suniUnifyPair.addAll(thisAsPair.getAllSubstitutions());