The Basic Logic Dialect of the Rule Interchange Format - A Tutorial Reconstruction

Syntactically, RIF-BLD has a number of extensions to achieve support for:

• • objects and frames as in F-Logic ,
  • internationalized resource identifiers (or IRIs, defined by RFC 3987) as identifiers for concepts,
  • XML Schema data types.

RIF is designed to enable interoperability among rule languages in general, and its uses are not limited to the Web.

Terms

RIF-BLD defines the following categories of terms:

• Constants
• Variables
• Positional Terms
• Terms with Named Arguments
• Equality Terms
• Classification terms (Membership and Subclass terms)
• Frames
• External Terms

Formulas

RIF-BLD defines the following categories of formulas:

• Atomic Formulas
• Conjunctions
• Disjunctions
• Formulas with existentially quantified variables
• Implications
• Universally quantified implications
• Group formulas
• Documents

While the first five formula categories are somehow similar with well-known logical concepts, the last two are not straightforward for standard users.

RIF Rules

References

• RIF-BLD (the Basic Logic Dialect of the Rule Interchange Format).
• RIF-BLD corresponds to the language of definite Horn rules (see Horn Logic) with equality and with a standard first-order semantics.