minor editorial comments on rdf-concepts

This document is an utter joy to read.   A perfect example of "as simple 
as possible, but no simpler."

A few minor comments:

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Minor typo:  :-)


    The syntactic restrictions on blank node identifiers, if any,
    therefore also depend on the concrete RDF syntax or implementation.
    The syntactic restrictions on blank node identifiers, if any,
    therefore also depend on the concrete RDF syntax or implementation.

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I guess Literal Equality is in the process of being edited -- it doesn't 
make sense to have "Literal equality" and "Literal term equality" next 
to each other like that.

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    This allows the system to map IRIs back to a blank node if needed.

(plural vs singular)

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Section 4.2 should probably not be marked "non-normative" since it 
contains an RFC 2119 keyword.

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    and implementations may not permit control codes in the |#x1-#x1F|
    range.

The "may not" construct is often ambiguous (as in this case) and may not 
be used in specs.  :-)  Please rephrase, perhaps as "might not".