question about an XSD 1.1 schema and XPath 2.0

Hi all,
     I'm testing an assertion in XSD 1.1 validation as following,

<xs:assertion test="(1,2,3) instance of xs:anyAtomicType*"/>
(this doesn't depend on any information, from an input XML document)

Xerces XSD 1.1 engine reports an error message with following contents,
"XPST0051 - Type not defined: xs:anyAtomicType"

But Saxon-EE embedded within oXygen XML 19.1 reports the validation as
succeeded.

When I run the following assertion,
<xs:assertion test="(1,2,3) instance of xs:integer*"/>

Both Xerces XSD 1.1 engine & Saxon do not report any validation failure.

The XPath 2.0 specification (https://www.w3.org/TR/xpath20), in section
"2.5 Types" says,
<quote>
[Definition: A schema type is a type that is (or could be) defined using
the facilities of [XML Schema] (including the built-in types of [XML
Schema]).] A schema type can be used as a type annotation on an element or
attribute node (unless it is a non-instantiable type such as xs:NOTATION or
xs:anyAtomicType, in which case its derived types can be so used).
</quote>

This reference from XPath 2.0 specification, makes me conclude that Xerces
XSD 1.1 engine is right & Saxon is wrong for the example posted.

Am I correct in my analysis?



-- 
Regards,
Mukul Gandhi