diff --git a/src/main/java/de/uni_jena/cs/fusion/abecto/processor/AbstractMappingProcessor.java b/src/main/java/de/uni_jena/cs/fusion/abecto/processor/AbstractMappingProcessor.java
index a45b0fba..21e1163d 100644
--- a/src/main/java/de/uni_jena/cs/fusion/abecto/processor/AbstractMappingProcessor.java
+++ b/src/main/java/de/uni_jena/cs/fusion/abecto/processor/AbstractMappingProcessor.java
@@ -28,6 +28,9 @@
 public abstract class AbstractMappingProcessor<P extends ParameterModel> extends AbstractMetaProcessor<P>
 		implements MappingProcessor<P> {
 
+	/** The known positive and negative mappings. */
+	protected Collection<Mapping> knownMappings;
+
 	/**
 	 * Computes the mappings of two models. The mappings may contain category meta
 	 * data.
@@ -44,7 +47,7 @@ public abstract Collection<Mapping> computeMapping(Model model1, Model model2, U
 	@Override
 	public final void computeResultModel() throws Exception {
 		// collect known mappings
-		Collection<Mapping> knownMappings = Mappings.getMappings(this.metaModel);
+		this.knownMappings = Mappings.getMappings(this.metaModel);
 
 		for (Entry<UUID, Model> i : this.inputGroupModels.entrySet()) {
 			UUID ontologyId1 = i.getKey();