Don't check including clusters --> if they was equal duplicates was found..

dmn-verifier-app/src/main/java/de/unikoblenz/fgbks/dmn/core/verifier/SubsumptionRules.java

@@ -113,19 +113,21 @@ public class SubsumptionRules extends AbstractVerifier {
         }
       }
       // check for subsets, that includes other subsets and remove them
+
       for (int x = 0; x < clusters.size(); x++) {
         if (clusters.get(x) != null) {
           Set<Value> c1 = clusters.get(x);
-          for (int y = 0; y < clusters.size(); y++) {
+          for (int y = x + 1; y < clusters.size(); y++) {
             if (clusters.get(y) != null) {
               Set<Value> c2 = clusters.get(y);
-              if (c1.containsAll(c2) && x != y) {
+              if (c1.containsAll(c2) && c2.containsAll(c1)) {
                 clusters.set(y, null);
               }
             }
           }
         }
       }
+
       // recursively search next row for subsumption with all clusters
       for (int x = 0; x < clusters.size(); x++) {
         if (clusters.get(x) != null) {