diff --git a/src/main/scala/com/dogfooter/rdfs/naive/NaiveRunningTask.scala b/src/main/scala/com/dogfooter/rdfs/naive/NaiveRunningTask.scala
index cda5140c85d2d37e79be77d3dff3f7fe565fca5e..9e46a53941aad948eccb5a086f4b943c5b56cb99 100644
--- a/src/main/scala/com/dogfooter/rdfs/naive/NaiveRunningTask.scala
+++ b/src/main/scala/com/dogfooter/rdfs/naive/NaiveRunningTask.scala
@@ -67,7 +67,7 @@ class NaiveRunningTask {
     val RDD_JOIN_RULE_2 = Naive.rule2Index(RDD_ALPHA_DOMAIN, RDD_JOIN_RULE_7)
     val RDD_JOIN_RULE_3 = Naive.rule3Index(RDD_ALPHA_RANGE, RDD_JOIN_RULE_7)
 
-    val RDD_JOIN_RULE_2_3 = RDD_ALPAH__TYPE.union(RDD_JOIN_RULE_2).union(RDD_JOIN_RULE_3)
+    val RDD_JOIN_RULE_2_3 = RDD_ALPAH__TYPE.union(RDD_JOIN_RULE_2).union(RDD_JOIN_RULE_3).map(t => t.mkString("\t")).distinct().map(line => line.split("\t"))
 
     val RDD_JOIN_RULE_9 = Naive.rule9Index(RDD_JOIN_RULE_11, RDD_JOIN_RULE_2_3)