diff --git a/ontologies/math.ttl b/ontologies/math.ttl
index c3cc76a..5a33cb9 100644
--- a/ontologies/math.ttl
+++ b/ontologies/math.ttl
@@ -8,6 +8,8 @@
 
 <http://openmath.org/vocab/math>
   rdf:type owl:Ontology ;
+  owl:imports <http://www.w3.org/2000/01/rdf-schema> ,
+              <http://www.w3.org/1999/02/22-rdf-syntax-ns> 
 .
 :Application
   rdf:type owl:Class ;
@@ -378,4 +380,4 @@ OpenMath objects can be attributed with OpenMath foreign objects, which are cont
 .
 :variables
   rdf:type owl:ObjectProperty ;
-.
\ No newline at end of file
+.