Re: ldp-ISSUE-75 (monotonicity): rdf:membershipProperty makes LDP PATCHing non-monotonic [Linked Data Platform core]

Given that a LDPC is defined as a collection of same-subject, same-predicate triples, my reaction to this issue to is to simply refuse a PATCH with a triple which fails outside of this SS-SP definition.

Roger

> ldp-ISSUE-75 (monotonicity): rdf:membershipProperty makes LDP PATCHing non-monotonic [Linked Data Platform core]
> 
> http://www.w3.org/2012/ldp/track/issues/75
> 
> Raised by: Henry Story
> On product: Linked Data Platform core
> 
> The current spec says that:
> 
> [[
> 5.2.5 An LDPC must contain one triple containing the ldp:membershipPredicate or ldp:membershipPredicateInverse predicate when the membership predicate is not rdfs:member.
> ]]
> 
> ie. rdfs:member is a default property.
> 
> So from 
> 
> <> ldp:Container .
> 
> one can deduce that 
> 
> <> ldp:Container ;
>   ldp:membershipPredicate rdf:member .
> 
> but if one then PATCHes the above LDPC by adding say
>   { <> ldp:membershipPredicate foaf:depiction } 
> then one can no longer deduce that {<> ldp:membershipPredicate rdf:member } which
> means that appending { <> ldp:membershipPredicate xxx } is a non-monotonic 
> process. 
> 
> Would one not then also by doing this suddenly make a LDPC that had members not 
> have any at all? It seems that the spec needs to say something about this.
> 
> This seems to be one more argument in favor of ISSUE-71 .
> 
> 
>