diff --git a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index 0e396810d..3f9466cfa 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -566,15 +566,29 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 						                              .filter(x -> b.contains(x))
 						                              //.filter(y -> abhSubst.contains(y))
 						                              .collect(Collectors.toCollection(HashSet::new));
-				Set<PlaceholderType> vars = durchschnitt.stream().map(x -> (PlaceholderType)x.getLhsType()).collect(Collectors.toCollection(HashSet::new));
+				//Set<PlaceholderType> vars = durchschnitt.stream().map(x -> (PlaceholderType)x.getLhsType()).collect(Collectors.toCollection(HashSet::new));
 				int len = nextSetasList.size();
-				nextSetasList = nextSetasList.stream().filter(x -> {
-					//Boolean ret = false;
-					//for (PlaceholderType var : vars) {
-					//	ret = ret || x.stream().map(b -> b.getLhsType().equals(var)).reduce((c,d) -> c || d).get();
-					//}
-					return (!x.containsAll(durchschnitt));
-				}).collect(Collectors.toCollection(ArrayList::new));
+				if (!durchschnitt.isEmpty()) {
+					UnifyPair groundBasepair = res.iterator().next().iterator().next().getGroundBasePair().get();
+					Set<UnifyPair> undefRes = res.stream().reduce((y,z) -> { y.addAll(z); return y;}).get();
+					Set<Set<UnifyPair>> reducedUndefResSubst = undefRes.stream()
+							.map(x -> x.getAllSubstitutions()).map(y -> { y.removeAll(durchschnitt); return y;})
+							.collect(Collectors.toCollection(HashSet::new));
+					Set<UnifyPair> resGroundBasepairs = undefRes.stream().map(x -> x.getGroundBasePair().get()).collect(Collectors.toCollection(HashSet::new));
+					if (res.size() > 1) {
+						System.out.println();
+					}
+					Set<UnifyPair> reducedAbhSubst = new HashSet<>(abhSubst);
+					reducedAbhSubst.removeAll(durchschnitt);
+					nextSetasList = nextSetasList.stream().filter(x -> {
+						//Boolean ret = false;
+						//for (PlaceholderType var : vars) {
+						//	ret = ret || x.stream().map(b -> b.getLhsType().equals(var)).reduce((c,d) -> c || d).get();
+						//}
+						return (!x.containsAll(durchschnitt));
+					}).filter(y -> couldBecorrect(reducedAbhSubst, groundBasepair, y))
+							.collect(Collectors.toCollection(ArrayList::new));
+				}
 				writeLog("abhSubst: " + abhSubst.toString());
 				writeLog("a: " + a.toString());
 				writeLog("Durchschnitt: " + durchschnitt.toString());
@@ -598,7 +612,34 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		return result;
 	}
 	
-
+	protected boolean couldBecorrect(Set<UnifyPair> reducedAbhSubst, UnifyPair groundBasepair, Set<UnifyPair> nextElem) {
+		reducedAbhSubst.add(groundBasepair);
+		reducedAbhSubst.addAll(nextElem);
+		Optional<Set<UnifyPair>> substRes = rules.subst(reducedAbhSubst);
+		if (!substRes.isPresent()) {
+			return true;
+		}
+		else {
+			UnifyPair checkPair = substRes.get().stream().filter(x -> x.getGroundBasePair().get().equals(groundBasepair)).findFirst().get();
+			if ((checkPair.getLhsType() instanceof PlaceholderType) || (checkPair.getRhsType() instanceof PlaceholderType)) {
+				Set<UnifyPair> up = new HashSet<>();
+				up.add(checkPair);
+				Set<UnifyPair> undef = new HashSet<>();
+				calculatePairSets(up, fc, undef);
+				if (undef.isEmpty()) {
+					return true;
+				}
+				else {
+					return false;
+				}
+			}
+			else {
+			  //Pair type <. type' betrachten TODO PL 2018-10-09		
+			}
+		}
+		return true;
+	}
+	
 	protected boolean isUndefinedPairSet(Set<UnifyPair> s) {
 		if (s.size() >= 1 ) {
 			Boolean ret = s.stream().map(x -> x.isUndefinedPair()).reduce(true, (x,y)-> (x && y));
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java b/src/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java
index 86e13e1d7..dd1858365 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java
@@ -4,6 +4,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 
 
@@ -151,6 +152,18 @@ public class UnifyPair {
 		return ret;
 	}
 	
+	public Optional<UnifyPair> getGroundBasePair () {
+		if (basePair == null) {
+			return Optional.empty();
+		}
+		if (basePair.getBasePair() == null) {
+			return Optional.of(basePair);
+		}
+		else {
+			return basePair.getGroundBasePair();
+		}
+	}
+	
 	public Boolean wrongWildcard() {
 		return lhs.wrongWildcard() || rhs.wrongWildcard();
 	}