<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:owlx="http://www.w3.org/2003/05/owl-xml" xmlns:swrlx="http://www.w3.org/2003/11/swrlx" xmlns:ruleml="http://www.w3.org/2003/11/ruleml" targetNamespace="http://www.w3.org/2003/11/swrlx" elementFormDefault="qualified" attributeFormDefault="qualified">

  <xsd:import namespace="http://www.w3.org/2003/05/owl-xml" schemaLocation="owlx/schema/owl1-dl.xsd"/>

  <xsd:import namespace="http://www.w3.org/2003/11/ruleml" schemaLocation="ruleml.xsd"/>

  <xsd:annotation>
    <xsd:documentation>
      XML Schema driver for SWRL 0.6
      The root element of SWRL documents for the XML
      Concrete Syntax must be the Ontology element. 
    </xsd:documentation>
  </xsd:annotation>

  <xsd:element name="Ontology"> 
    <xsd:annotation>
      <xsd:documentation>
        This is the root element of SWRL documents 
        in the XML Concrete Syntax.  It extends owlx:Ontology
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType> 
      <xsd:sequence>
        <xsd:sequence minOccurs="0" maxOccurs="unbounded">
          <xsd:choice>
            <!-- Header elements --> 
            <xsd:element ref="owlx:VersionInfo"/>
            <xsd:element ref="owlx:PriorVersion"/>
            <xsd:element ref="owlx:BackwardCompatibleWith"/>
            <xsd:element ref="owlx:IncompatibleWith"/>
            <xsd:element ref="owlx:Imports"/>
            <xsd:element ref="owlx:Annotation"/>

            <!-- Class elements --> 
            <xsd:element ref="owlx:Class"/>
            <xsd:group ref="owlx:classElements"/>
  
            <!-- Property elements --> 
            <xsd:element ref="owlx:DatatypeProperty"/>
            <xsd:element ref="owlx:ObjectProperty"/>
            <xsd:element ref="owlx:SubPropertyOf"/>
            <xsd:element ref="owlx:EquivalentProperties"/> 
   
            <!-- Instances --> 
            <xsd:element ref="owlx:Individual"/>
            <xsd:element ref="owlx:SameIndividual"/>
            <xsd:element ref="owlx:DifferentIndividuals"/>

            <!-- SWRL extensions -->
            <xsd:element ref="ruleml:imp"/>
            <xsd:element ref="ruleml:var"/>
          </xsd:choice>
        </xsd:sequence>
      </xsd:sequence>
      <xsd:attribute ref="owlx:name"/>
    </xsd:complexType>

    <!-- XXX:  clone for rule names, etc. -->
    <xsd:unique name="classNameUniqueness"> 
      <xsd:annotation>
        <xsd:documentation>
          This constraint ensures that every class name is unique 
          in a single OWL document. 
        </xsd:documentation>
      </xsd:annotation>
      <xsd:selector xpath="owlx:Class"/> 
      <xsd:field xpath="@owlx:name"/> 
    </xsd:unique>
  </xsd:element>

  <xsd:group name="atom">
    <xsd:choice>
      <xsd:element ref="swrlx:classAtom"/>
      <xsd:element ref="swrlx:datarangeAtom"/>
      <xsd:element ref="swrlx:individualPropertyAtom"/>
      <xsd:element ref="swrlx:datavaluedPropertyAtom"/>
      <xsd:element ref="swrlx:sameIndividualAtom"/>
      <xsd:element ref="swrlx:differentIndividualAtom"/>
      <xsd:element ref="swrlx:builtinAtom"/>
    </xsd:choice>
  </xsd:group>

  <xsd:element name="classAtom">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:group ref="owlx:description"/>
        <xsd:group ref="swrlx:iObject"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="datarangeAtom">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:group ref="owlx:datarange"/>
        <xsd:group ref="swrlx:dObject"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="individualPropertyAtom">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:group ref="swrlx:iObject"/>
        <xsd:group ref="swrlx:iObject"/>
      </xsd:sequence>
      <xsd:attribute name="property" type="owlx:IndividualPropertyName" use="required"/>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="datavaluedPropertyAtom">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:group ref="swrlx:iObject"/>
        <xsd:group ref="swrlx:dObject"/>
      </xsd:sequence>
      <xsd:attribute name="property" type="owlx:DataPropertyName" use="required"/>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="sameIndividualAtom">
    <xsd:complexType>
      <xsd:sequence minOccurs="0" maxOccurs="unbounded">
        <xsd:group ref="swrlx:iObject"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="differentIndividualAtom">
    <xsd:complexType>
      <xsd:sequence minOccurs="0" maxOccurs="unbounded">
        <xsd:group ref="swrlx:iObject"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="builtinAtom">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:group ref="swrlx:dObject" minOccurs="1" maxOccurs="unbounded"/>
      </xsd:sequence>
    <xsd:attribute name="builtin" type="swrlx:BuiltinName" use="required"/>
    </xsd:complexType>
  </xsd:element>

  <xsd:group name="iObject">
    <xsd:choice>
      <xsd:element ref="owlx:Individual"/>
      <xsd:element ref="ruleml:var"/>
    </xsd:choice>
  </xsd:group>

  <xsd:group name="dObject">
    <xsd:choice>
      <xsd:element ref="owlx:DataValue"/>
      <xsd:element ref="ruleml:var"/>
    </xsd:choice>
  </xsd:group>

  <xsd:simpleType name="BuiltinName">
    <xsd:restriction base="xsd:anyURI"/>
  </xsd:simpleType>

</xsd:schema>