The fresh datatype identifiers inside DTS enforce the following limits

• Wef the signature = has an arrow xcheaters profili expression (s s)?k then I₌ must map D_s?D_s to D_k.

The effect of datatypes. If dt ? DTS, let LS_dt denote the lexical space of dt, VS_dt denote its value space, and L_dt: LS_dt > VS_dt the lexical-to-value-space mapping. Then the following must hold:

• VS_dt ? D; and
• For each constant "illuminated"^^dt such that lit ? LS_dt, I_C("lit"^^dt) = L_dt(lit).

RIF-FLD does not impose special requirements on I_C for constants in the symbol spaces that do not correspond to the identifiers of the datatypes in DTS. Dialects ple of such a restriction could be a requirement that no constant in a particular symbol space (such as rif:regional) can be mapped to VS_dt of a datatype dt.

3.5 Annotations additionally the Certified Semantics

RIF-FLD annotations are stripped before the mappings that constitute RIF-FLD semantic structures are applied. Likewise, they are stripped before applying the knowledge valuation, TVal_I, defined in the next section. Thus, identifiers and metadata have no effect on the formal semantics.

Note that even though annotations of the RIF-FLD formulas is forgotten from the semantics, they’re extracted from the XML devices. Because annotations are portrayed by body type terms, they can be reasoned having by the rules. New physical stature conditions accustomed show metadata may then getting given to other formulas, thus enabling need about metadata. Although not, RIF cannot define one real semantics getting metadata.

3.6 Interpretation from Low-document Algorithms

This section defines how a semantic structure, I, determines the truth value TVal_I(?) of a RIF-FLD formula, ?, where ? is any formula other than a document formula or a remote formula. Truth valuation of document formulas is defined in the next section.

To this end, we define a mapping, TVal_I, from the set of all non-document formulas to TV. Note that the definition implies that TVal_I(?) is defined only if the set DTS of the datatypes of I includes all the datatypes mentioned in ?.

• I_truth(I(x = y)) = t if I(x) = I(y) and I_truth(I(x = y)) = f otherwise.

To ensure that the operator ## is transitive, i.e., cstep one ## c2 and c2 ## c3 imply c1 ## c3, the following is required:

• For all well-formed terms c1, c2, c3: glb_t(TVal_I(c1 ## c2), TVal_I(c2 ## c3)) ?_tTVal_I(c1 ## c3).

Note that this is a restriction on I_truth and the mapping I, which is expressed in a more succinct form using TVal_I.

To ensure that all members of a subclass are also members of the superclass, i.e., o # cl and cl ## scl imply o # scl, the following is required:

• For all well-formed terms o, cl, scl: glb_t(TVal_I(o # cl), TVal_I(cl ## scl)) ?_tTVal_I(o # scl).

Note that this is a restriction on I_truth and the mapping I, which is expressed in a more succinct form using TVal_I.

• TVal_I(o[a₁->v₁ . a_k->v_k]) = glb_t(TVal_I(o[a₁->v₁]), . TVal_I(o[a_k->v_k])).

Observe that this is a restriction on I_truth and the mapping I. For brevity, it is expressed in a more succinct form using TVal_I.

Note that, by definition, External(t loc) is well-formed only if it is an instantiation of an external schema. Furthermore, by the definition of coherent sets of external schemas, it can be an instantiation of at most one external schema, so I(External(t loc)) is well-defined.

To ensure the intended semantics for the RIF-FLD reserved connectives and quantifiers, the following restrictions are imposed (observe that all these are restrictions on I_truth and the mapping I, which are expressed via TVal_I, for brevity):

The symmetric negation, Neg, is sufficiently general to capture many different kinds of such negation. For instance, classical negation would, in addition, require TVal_I(Neg ?) =