<?xml version=“1.0”?> <xs:schema xmlns:xs=“www.w3.org/2001/XMLSchema”>
<xs:complexType name="A"> <xs:all> <xs:element name="b" type="xs:string" minOccurs="0"/> </xs:all> </xs:complexType> <xs:element name="a" type="A"/>
</xs:schema>
<?xml version=“1.0”?> <xs:schema xmlns:xs=“www.w3.org/2001/XMLSchema”>
<xs:complexType name="A"> <xs:all> <xs:element name="b" type="xs:string" minOccurs="0"/> </xs:all> </xs:complexType> <xs:element name="a" type="A"/>
</xs:schema>