For-instance, the brand new trademark of this an icon
p might allow p to appear in a term of the form f(p), but disallow it to occur in a term like p(a 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 subsequent constraints towards the style of an effective form of types of identity otherwise formula. Such as for example, variables or aggregate conditions is almost certainly not invited in certain towns.
Semantic build. That it construction talks of the idea of a beneficial semantic structure (called interpretation from the literary works [Enderton01, Mendelson97]). Semantic structures are used to interpret algorithms and also to establish logical entailment. Just as in new syntax, this design has plenty of components one RIF reasoning languages can specialise to match their requirements. This type of mechanisms become:
Each RIF dialect that is derived from RIF-FLD would-be described within its own file
- Gang of information opinions. RIF-FLD was designed to match dialects that assistance cause having inconsistent and unsure pointers. Most of the logics that will handle this type of situations was multi-cherished. For that reason, RIF-FLD postulates that there’s a collection of knowledge values, Television, with the values t (true) and you will f (false) and maybe other people. Including, new RIF Basic Reason Dialect [RIF-BLD] was two-appreciated, but other dialects have extra details thinking.
- Semantic structures. Semantic structures decide how various icons about alphabet off an excellent dialect was interpreted and just how basic facts philosophy are assigned to formulas.
- 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 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 framework. So it build talks of the overall values getting mapping the brand new presentation syntax away from RIF-FLD on the concrete XML interchange format. This includes:
For every single RIF dialect which is based on RIF-FLD was demonstrated in very own document
- A specs of your own XML syntax getting RIF-FLD, like the related XML Schema document.
- A requirements of a single-to-you to definitely mapping from the demonstration syntax from RIF-FLD in order to its XML sentence structure. So it mapping need certainly to chart any well-designed algorithm off RIF-FLD so you can a keen XML including file that is legitimate in respect with the aforementioned XML Schema file.
It requirements ‘s the current write of your own RIF-FLD definition. The first such as for instance dialect, the brand new RIF First Logic Dialect, try revealed inside the [RIF-BLD]. A center dialect abdlmatch visitors, which is discussed because of the further specializing RIF-BLD, is given when you look at the [RIF-Core].