diff --git a/hipster-core/src/main/java/es/usc/citius/hipster/model/function/impl/BinaryOperation.java b/hipster-core/src/main/java/es/usc/citius/hipster/model/function/impl/BinaryOperation.java
index dcf20b0..4713b23 100644
--- a/hipster-core/src/main/java/es/usc/citius/hipster/model/function/impl/BinaryOperation.java
+++ b/hipster-core/src/main/java/es/usc/citius/hipster/model/function/impl/BinaryOperation.java
@@ -30,7 +30,7 @@
  * @author Pablo Rodríguez Mier <<a href="mailto:pablo.rodriguez.mier@usc.es">pablo.rodriguez.mier@usc.es</a>>
  * @author Adrián González Sieira <<a href="adrian.gonzalez@usc.es">adrian.gonzalez@usc.es</a>>
  */
-public class BinaryOperation<E> implements BinaryFunction<E> {
+public class BinaryOperation<E extends Comparable<E>> implements BinaryFunction<E> {
 
 	private E maxElem;
 	private E identityElem;
@@ -45,9 +45,9 @@ public class BinaryOperation<E> implements BinaryFunction<E> {
 	 */
 	public BinaryOperation(BinaryFunction<E> operation, E identityElem, E maxElem) {
         // Check properties
-        assert operation.apply(identityElem, maxElem).equals(maxElem);
-        assert operation.apply(maxElem, identityElem).equals(maxElem);
-        assert operation.apply(identityElem, identityElem).equals(identityElem);
+        assert operation.apply(identityElem, maxElem).compareTo(maxElem) == 0;
+        assert operation.apply(maxElem, identityElem).compareTo(maxElem) == 0;
+        assert operation.apply(identityElem, identityElem).compareTo(identityElem) == 0;
         //Preconditions.checkArgument(operation.apply(identityElem, maxElem).equals(maxElem), "Property error: I x A != A");
         //Preconditions.checkArgument(operation.apply(maxElem, identityElem).equals(maxElem), "Property error: A x I != A");
         //Preconditions.checkArgument(operation.apply(identityElem, identityElem).equals(identityElem), "Property error: I x I != I");