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This is how a proposed design constraint should look like (copy-paste when adding a new proposal):

Offer module construct for scoped positive and negation as failure queries

Full Statement

Modules (sometimes also called 'contexts', 'scopes' or even 'models') have already been used in rule systems of the pre-Web era to structure non-trivial rulebases into semantically related clusters, to confine the search space of (inferential) query answering to the relevant subset of rules, and to 'close off' the definition of certain predicates. All of this becomes even more important in the open-ended environment of the Web. In particular, negation as failure queries can be made relative to the 'closed world' of a module. Modules also support rulebase interoperation and interchange by allowing to collect the subsets of rules that act as the source and the target for partial interoperation or interchange (which is more realistic than total interoperation or interchange).

Position in the DC structure


The DC Support LP semantics with negation as failure and strong negation depends on that one.


This design constraint is derived from the charter's envisioned Scoped Negation-As-Failure extension, one or more of the rule systems listed in RIFRAF (Flora 2, TRIPLE), and a UC not covered in the current version of UCR.


RIF without that is useless for me / RIF without that is of limited use for me.


HaroldBoley, MichaelKifer, MichaelSintek, AxelPolleres