Fix bug for OWLObjectSubPropertyOfAxiom

A version of the rule with an empty suffix was missing. Note that this
is not completely clear from the paper.

2 files changed, 6 insertions, 7 deletions

diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/CanonicalModel.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/CanonicalModel.scala
index c605e51..5001c8a 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/CanonicalModel.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/CanonicalModel.scala
@@ -247,11 +247,10 @@ class CanonicalModel(val ontology: RSAOntology) {
         }
 
         case a: OWLSubObjectPropertyOfAxiom => {
-          val (factsF, rulesF) =
-            super.convert(a, term, unsafe, NoSkolem, Forward)
-          val (factsB, rulesB) =
-            super.convert(a, term, unsafe, NoSkolem, Backward)
-          (factsF ::: factsB, rulesF ::: rulesB)
+          val (facts, rules) = List(Empty, Forward, Backward)
+            .map(super.convert(a, term, unsafe, NoSkolem, _))
+            .unzip
+          (facts.flatten, rules.flatten)
         }
 
         case a => super.convert(a, term, unsafe, skolem, suffix)
diff --git a/src/test/scala/uk/ac/ox/cs/rsacomb/CanonicalModelSpec.scala b/src/test/scala/uk/ac/ox/cs/rsacomb/CanonicalModelSpec.scala
index a588ae8..0d18e66 100644
--- a/src/test/scala/uk/ac/ox/cs/rsacomb/CanonicalModelSpec.scala
+++ b/src/test/scala/uk/ac/ox/cs/rsacomb/CanonicalModelSpec.scala
@@ -218,13 +218,13 @@ class Ontology1_CanonicalModelSpec
 
   renderer.render(
     SsubPropertyOfT
-  ) should "produce 2 rules" in {
+  ) should "produce 3 rules" in {
     val term = Variable.create("X")
     val unsafe = ontology.unsafeRoles
     val (facts, rules) =
       converter.convert(SsubPropertyOfT, term, unsafe, NoSkolem, Empty)
     facts shouldBe empty
-    rules should have length 2
+    rules should have length 3
   }
 
 }