- Replacing NEWCONNECTIVE with zero or more new connective symbols. Dialects cannot keep the extension point.
- Losing zero or more of your own predetermined connective signs mentioned above. Dialects do not redefine the fresh semantics of one’s predefined connectives, however.
- Replacing NEWQUANTIFIER with zero or more new quantifier symbols. Dialects cannot keep the extension point.
- Dropping no or more of your own predetermined quantifier signs mentioned above. Yet not, dialects dont redefine the fresh new semantics of your 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: Minute, Max, Number, Avg, Contribution, Prod, Set, and Purse. 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.
- Shedding no or higher of the predetermined aggregate attributes in the list above. Yet not, languages usually do not redefine brand new semantics of one’s predetermined aggregate functions.
Like with almost every other extension items, this is not a genuine icon on the alphabet, however, good placeholder one languages are meant to make up for zero or more real the brand new alphabet icons.
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 Exterior 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 fetlife the symbol Import is an import directive. The Module directive is used to connect remote terms with the actual remote RIF documents.
Finally, the symbol File is used for specifying RIF-FLD documents and the symbol Group is used to organize RIF-FLD formulas into collections. ?
2.step 3 Symbol Areas
These types of and other abbreviations will be put since prefixes on the lightweight URI-such as for instance notation [CURIE], an effective notation getting brief icon out-of Eye [RFC-3987]. The specific meaning of so it notation in RIF is set within 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,