--- a/app/query.service.ts	Thu Jan 21 19:30:57 2016 +0100
+++ b/app/query.service.ts	Thu Jan 21 20:07:32 2016 +0100
@@ -15,6 +15,7 @@
     public openMindBaseUrl = 'https://ismi-dev.mpiwg-berlin.mpg.de/om4-ismi/';
     //public openMindBaseUrl = 'http://localhost:18080/ismi-richfaces/';
     public excludedAttributes = {'type': true};
+    public invRelPrefix = '<- ';
     public state: QueryState;
     public ismiObjectTypes: any;
     
@@ -46,6 +47,7 @@
     
     getQueryOptions(queryMode: QueryMode) {
         var options = [];
+        if (queryMode == null) return options;
         if (queryMode.id === 'type_is') {
             options = this.ismiObjectTypes;
         } else if (queryMode.id === 'relation_is') {
@@ -109,7 +111,14 @@
              */
             if (step.mode.id === 'relation_is') {
                 nIdx += 1;
-                queryMatch += `-[:\`${step.relationType}\`]->(n${nIdx})`;
+                var rel = step.relationType;
+                if (rel.indexOf(this.invRelPrefix) == 0) {
+                    // inverse relation
+                    rel = rel.substr(this.invRelPrefix.length);
+                    queryMatch += `<-[:${rel}]-(n${nIdx})`;
+                } else {
+                    queryMatch += `-[:\`${rel}\`]->(n${nIdx})`;
+                }
                 queryReturn =  `RETURN n${nIdx}`;
                 returnType = 'node';
             }
@@ -155,9 +164,12 @@
             }
             
         });
+        // compose query
         resultQuery = queryMatch + '\n' + queryWhere + '\n' + queryReturn;
+        // compose query for attributes of result
         attributesQuery = queryMatch + ' ' + queryWhere + ` WITH DISTINCT keys(n${nIdx}) AS atts`
             + ` UNWIND atts AS att RETURN DISTINCT att ORDER BY att`;
+        // compose query for relations of result
         relationsQuery = queryMatch + '-[r]-() ' + queryWhere + ' RETURN DISTINCT type(r)';
         this.state.resultCypherQuery = resultQuery;
         this.state.cypherQueryParams = queryParams;
@@ -222,8 +234,11 @@
                  */
                 if (this.state.relationsCypherQuery) {
                     resIdx += 1;
-                    this.state.nextQueryRelations = data.results[resIdx].data.map(elem => elem.row[0])
+                    var rels = data.results[resIdx].data.map(elem => elem.row[0])
                     .filter(elem => elem[0] != "_");
+                    // add inverse relations
+                    var invrels = rels.concat(rels.map((r) => this.invRelPrefix + r));
+                    this.state.nextQueryRelations = invrels;
                 }
             },
             err => console.error("neo4j result error=", err),