Unqualified type

I've encountered a schema that looks like this:

    <schema xmlns="http://www.w3.org/2001/XMLSchema" 
        targetNamespace="http://www.mydomain.com/types"
        xmlns:xsd="http://www.w3.org/2001/XMLSchema"
        xmlns:tns="http://www.mydomain.com/types">
      <complexType name="coordinates">
        <sequence>
          <element name="x" type="double"/>
          <element name="y" type="double"/>
        </sequence>
      </complexType>
    </schema>

The object of my confusion are the x and y elements whose types are not
fully qualified.  According to the examples in Vlist's book, this is
legal... my question is how it should be interpreted.  Is an unqualified
type assumed to be a type in the target namespace (which I believe would
make this schema illegal) or in the default namespace (I think that's the
proper term for it :)

Brenda Bell
Sr. Software Architect
Juice Software, Inc.
Phone: 603.428.3994
Cell:  603.494.8206
Fax:   603.428.8713
Email: bbell@juicesoftware.com
MSN:   bbell@theotherbell.com