possible stances with respect to multiple reification

I would find it useful to have an enumeration of the possible stances with 
respect to multiple reification.  I see four:

1/ Multiple reification is completely illegal so
    << :r | :a :b 42 >> :c :d .
    << :r | :a :b 43 >> :c :d .
is not an RDF graph, just as
    "abc" :b :c .
is not an RDF graph.

2/ Multiple reification is possible but something to be avoided, like
    :l rdf:first "abc" .
    :l rdf:first "def" .
    :l rdf:next rdf:nil .
is a valid RDF graph but is to be avoided or similar to
    :age rdfs:range xsd:int .
    :liz :age "abc" .
is a valid RDF graph but is to be avoided.  That is, these graphs do not make 
sense for any purpose.

3/ Multiple reification is possible but can cause problems and thus should not 
be encouraged, like
    :r rdfs:subPropertyOf rdfs:subPropertyOf .
    :r rdfs:subPropertyOf rdfs:subClassOf .
is a valid RDF graph but can cause problems or
    :age rdfs:range xsd:int .
    :liz :age :f .
is a valid RDF graph but can cause problems.  That is, anyone who creates 
these graphs should understand the consequences of what they are doing.

4/ Multiple reification is possible and has no negative connotations, like
    :liz :married :dick .
    :liz :married :eddie .
is a valid RDF graph and has no problems as far as RDF is concerned.


I have a preferred stance here, a stance I cannot live with, one I can live 
with, and one I am uncertain about.

peter

Received on Monday, 22 April 2024 13:21:51 UTC