diff --git a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index 3f9466cf..b1cbbe7b 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -571,8 +571,9 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				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;})
+					Set<Set<UnifyPair>> reducedUndefResSubstGroundedBasePair = undefRes.stream()
+							.map(x -> { Set<UnifyPair> su = x.getAllSubstitutions(); su.add(x.getGroundBasePair().get()); return su;})
+							.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) {