3.1.1.1 Resolving QNames to Expanded QNames
Under Semantics, you show a formal inference. Above the line,
it has "statEnv.namespace(NCName1) = URI-or-#NULL-NAMESPACE".  
This uses a 
predicate, "=", which you have not presented or defined.
Since this judgment is talking about equality of URIs, 
you probably mean the same conventions for deciding equality
as in other XML-related specifications, which is code-point
equality of Unicode strings.  I believe I have seen other 
uses of equality; you should have a section that defines this 
operator for all types that you use it on.  Section 2.1.2
"Notations for judgments" looks like a good spot.