diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java b/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java
index 2de2d18..31a2ca5 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java
@@ -104,7 +104,7 @@
 	protected LinkedHashMap<String, Object> makeDocGroup(String relation) {
 		LinkedHashMap<String, Object> term = new LinkedHashMap<String, Object>();
 		term.put("@type", "korap:docGroup");
-		term.put("relation", "relation:"+relation);
+		term.put("operation", "operation:"+relation);
 		term.put("operands", new ArrayList<Object>());
 		return term;
 	}
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryTree.java b/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryTree.java
index 4c663e2..a33bc2e 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryTree.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryTree.java
@@ -71,7 +71,7 @@
 
         if (nodeCat.equals("relation")) {
         	String operator = node.getChild(1).getChild(0).toStringTree(parser).equals("&") ? "and" : "or"; 
-            LinkedHashMap<String, Object> relationGroup = makeGroup(operator);
+            LinkedHashMap<String, Object> relationGroup = makeDocGroup(operator);
             putIntoSuperObject(relationGroup);
             objectStack.push(relationGroup);
             stackedObjects++;
@@ -98,7 +98,7 @@
                 term.put("match", "match:" + interpretMatch(match));
                 putIntoSuperObject(term);
             } else { // (valueNodes.size()==2)
-                LinkedHashMap<String, Object> termGroup = makeGroup("and");
+                LinkedHashMap<String, Object> termGroup = makeDocGroup("and");
                 ArrayList<Object> termGroupOperands = (ArrayList<Object>) termGroup.get("operands");
 
                 LinkedHashMap<String, Object> term1 = makeDoc();