The description of the resolve-uri function says (under "Rules"):


  If the $base argument is not supplied, then:

      If the static base URI in the static context is not absent, it is used as
        the effective value of $base.

      Otherwise, a dynamic error is raised: [err:FORG0002].


But then, later, under "Error conditions", it says:


   The first form of this function resolves $relative against the value of the
   base-uri property from the static context. A dynamic error is raised 
   [err:FONS0005] if the base-uri property is not initialized in the static 
   context.


This seems to be a contradiction about which of the 2 errors (FORG0002 or FONS0005) is raised, unless I'm missing something subtle about the static base URI.  It also seems that the paragraph in "Error conditions" should have a caveat that the error is only raised if $relative is not the empty sequence or an absolute URI.