- Replacing NEWCONNECTIVE with zero or more new connective symbols. Dialects cannot keep the extension point.
- Losing zero or higher of your own predefined connective signs mentioned above. Dialects don’t change the fresh new semantics of the predefined connectives, however.
- Replacing NEWQUANTIFIER with zero or more new quantifier symbols. Dialects cannot keep the extension point.
- Shedding zero or maybe more of one’s predetermined quantifier symbols mentioned above. Yet not, languages try not to change new semantics of one’s predetermined quantifiers.
In the actual presentation syntax, we will be linearizing the predefined quantifier symbols and write them as Exists ?X1. Xn and Forall ?X1. Xn instead of Exists?X1. Xn and Forall?X1. Xn.
Every quantifier symbol has an associated list of variables that are bound by that quantifier. For the standard quantifiers Exists?X1. Xn and Forall?X1. Xn, the associated list of variables is ?X1. Xn.
RIF-FLD reserves the following symbols for standard aggregate functions: Min, Maximum, Number, Avg, Share, Prod, Put, and Bag. Aggregate functions also have an extension point, NEWAGGRFUNC, which must be actualized. Dialects can specialize the aforesaid set of aggregate functions by
- Replacing NEWAGGRFUNC with zero or more new symbols for aggregate functions. Dialects cannot keep the extension point.
- Dropping no or higher of your own predetermined aggregate functions in the above list. But not, languages dont redefine the semantics of your own predefined aggregate attributes.
Just as in almost every other extension points, this is not a real icon about alphabet, but an excellent placeholder one to dialects are meant to replace zero or more actual new alphabet symbols.
The symbol Naf represents default negation, which is used in rule languages with logic programming and deductive database semantics. Examples of default negation include Clark’s negation-as-failure [Clark87], the well-founded negation [GRS91], and stable-model negation [GL88]. The name of the symbol Naf used here comes from negation-as-failure but in RIF-FLD this can refer to any kind of default negation.
The symbol Neg represents symmetric negation (as opposed to default negation, which is asymmetric because completely different inference rules are used to derive p and Naf p). Examples of symmetric negation include classical first-order negation, explicit negation, and strong negation [APP96].
=, #, and ## are used in formulas that define equality, class membership, and subclass relationships, respectively. The symbol -> is used in terms that have named arguments and in frame terms. The symbol External indicates that an atomic formula or a function term is defined externally (e.g., a built-in), Dialect is a directive used to indicate the dialect of a RIF document (for those dialects that require this), the symbols Foot and Prefix enable abridged representations of IRIs, and the symbol Transfer is an import directive. The Component directive is used to connect remote terms with the actual remote RIF documents.
The new symbols
Finally, the symbol File is used for specifying RIF-FLD documents and the symbol Class is used to organize RIF-FLD formulas into collections. ?
dos.step 3 Symbol Places
These types of and other abbreviations was made use of as the prefixes in the lightweight URI-including notation [CURIE], an effective notation for concise signal from Iris [RFC-3987]. The specific concept of it notation within the RIF is placed during the [RIF-DTB].
The set of all constant symbols in a RIF dialect is partitioned into a number of subsets, called symbol spaces, which are used to represent XML Schema datatypes, datatypes defined in other W3C specifications, such as rdf:XMLLiteral, and to distinguish other sets of constants. All constant symbols have a syntax (and sometimes also semantics) imposed by the symbol space to which they belong.
- xs: stands for the XML Schema URI
- rdf: stands for
- pred: stands for
- rif: stands for the URI of RIF,