p might allow p to appear in a term of the form f(p), but disallow it to occur in a term like p(good,b). The signature for f, on the other hand, might allow that symbol to appear in f(p) and f(p,q), but disallow f(p,q,r) and f(f). In this way, it is possible to control which symbols are used for predicates and which for functions, where variables can occur, and so on.
Gramsood dialect might impose after that limitations toward brand of a great version of particular identity otherwise algorithm. Instance, variables otherwise aggregate terminology is almost certainly not greeting in certain locations.
Semantic design. So it design represent the notion of a good semantic build (known as translation regarding literature [Enderton01, Mendelson97]). Semantic formations are widely used to interpret algorithms in order to describe analytical entailment. Just as in the latest syntax, it build includes loads of systems you to RIF reasoning dialects can be specialize to complement their demands. Such elements were:
Per RIF dialect which is based on RIF-FLD could be explained within its own file
- Band of realities beliefs. RIF-FLD was created to fit dialects that help need that have inconsistent and you will uncertain pointers. All logics that can handle these circumstances try multi-respected. Thus, RIF-FLD postulates that there’s a set of insights values, Tv, which includes the prices t (true) and you will f (false) and possibly anybody else. Such as for example, the newest RIF Earliest Logic Dialect [RIF-BLD] try two-respected, but other languages may have most specifics viewpoints.
- Semantic structures. Semantic formations regulate how different signs about alphabet out of a great dialect was interpreted as well as how truth thinking are allotted to algorithms.
- Datatypes. Some symbol spaces that are part of the RIF syntactic framework have fixed interpretations. For instance, symbols in the symbol space are always interpreted as sequences of Unicode characters, and a ? b for any pair of distinct symbols. A symbol space whose symbols have a fixed interpretation in any semantic structure is called a datatype.
- Entailment. This notion is fundamental to logic-based dialects. Given a set of formulas (e.g., facts and rules) G, entailment determines which other formulas necessarily follow from G. Entailment is the main mechanism underlying query answering in Databases, Logic antichat Programming, and the various reasoning tasks in Description Logics.
A set of formulas G logically entails another formula g if for every semantic structure I in some set S, if G is true in I then g is also true in I. Almost all logics define entailment this way. The difference lies in which set S they use. For instance, logics that are based on the classical first-order predicate calculus, such as most Description Logics, assume that S is the set of all semantic structures. In contrast, most Logic Programming languages use default negation. Accordingly, the set S contains only the so-called minimal Herbrand models [Lloyd87] of G and, furthermore, only the minimal models of a special kind. See [Shoham87] for a more detailed exposition of this subject.
XML serialization construction. So it construction talks of the general principles getting mapping the brand new demonstration sentence structure away from RIF-FLD toward concrete XML interchange structure. This includes:
For each and every RIF dialect which is derived from RIF-FLD is revealed with its individual document
- A requirements of your own XML syntax for RIF-FLD, including the relevant XML Schema document.
- A requirements out-of a one-to-one mapping on the speech syntax from RIF-FLD so you can their XML syntax. This mapping must chart one really-molded formula from RIF-FLD in order to a keen XML for example file which is appropriate in respect to your aforesaid XML Schema file.
It specs is the latest draft of RIF-FLD meaning. The first such as dialect, this new RIF Basic Reason Dialect, is actually discussed in the [RIF-BLD]. A key dialect, that’s defined because of the after that specializing RIF-BLD, are specified inside the [RIF-Core].