XPath and Namespace

[Mohana Ramaratnam]

If I have an instance document like so:   <Pipeline xmlns="http://nrg.wustl.edu/pipeline" xmlns:prov="http://www.nbirn.net/prov" xmlns:xdat="http://nrg.wustl.edu/xdat" xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://nrg.wustl.edu/xnat C:\\schema\pipeline.xsd"> <parameters>              <parameter>                     <name>fidldir</name>                     <value>/fidl/fidl_2.60/bin</value>              </parameter>              <parameter>                     <name>rlbdir</name>                     <value>/Pipeline/parameters/parameter[name='fidldir']/value/text() </value>              </parameter> </parameters> </Pipeline>   And I want to evaluate the xpath _expression_:   /Pipeline/parameters/parameter[name='fidldir']/value/text()   Is it necessary for the namespace prefix of pipeline: to be present in the _expression_ /Pipeline/parameters/parameter[name='fidldir']/value/text() for xpath to be evaluated correctly?   Ie should the _expression_ be:   /pipeline:Pipeline/pipeline:parameters/pipeline:parameter[pipeline:name='fidldir']/pipeline:value/text()   (as in the samples)   How do I set the namespace so that the instance document xpath _expression_ need not have the namespace prefixed. I have looked into XmlOptions and didn’t find anything useful.