[RIF-test] Consistency/NegativeConsistency tests

The topic of  Consistency/NegativeConsistency tests came up during the 
last
telecon.

If we have this type of test, would it mean that a BLD consumer will be 
required
to, or can optionally, have a consistency-checking mode, where it takes an 
input 
document and gives an answer - consistent or inconsistent?

The BLD spec doesn't define a consistent document. Can we define this
test as:  The document must be found consistent if there is some semantic
structure (interpretation) that is a model of the document, and 
inconsistent
otherwise.

Stella