Namespaces Present Two Challenges to Schema LanguagesNamespace DeclarationsTo Qualify Or Not to Qualify?Disruptive AttributesNamespaces and XPath ExpressionsReferencing Other NamespacesSchemas for XML, XML Base and XLinkXML AttributesXLink AttributesNamespace Behavior of Imported ComponentsImporting Schemas with No NamespacesChameleon DesignAllowing Any Elements or Attributes from a Particular Namespace