Output dataset section

spec/section/graphmap.md

@@ -81,3 +81,8 @@ However, in this example, RDF triples of the [=predicate=] `ex:title` are placed
 
 </aside>
 
+## Scope of Blank Nodes
+
+[=Blank nodes=] in the [=output dataset=] are scoped to a single [=RDF graph=]. If the same [=blank node identifier=] occurs in multiple [=RDF triples=] that are in the same graph, then the triples will share the same blank node. If, however, the same blank node identifier occurs in multiple graphs, then a distinct blank node be created for each graph. An RML-generated blank node can never be shared by two triples in two different graphs.
+
+This implies that triples generated from a single logical source row will have different subjects if the subjects are blank nodes and the triples are placed into different graphs.

spec/section/mapping.md

@@ -62,13 +62,14 @@ A <dfn>subject map</dfn> is a [=term map=]. It specifies a rule for generating t
 
 ## Typing Resources (rml:class)
 
-A [=subject map=] MAY have one or more _**class IRIs**_. They are represented by the `rml:class` property.
+A <dfn>class IRI</dfn> is an [=IRI=] that denotes an [=RDFS class=].
+A [=subject map=] MAY have one or more [=class IRIs=]. They are represented by the `rml:class` property.
 The values of the `rml:class` property MUST be [=IRIs=].
 For each [=RDF term=] generated by the [=subject map=], [=RDF triples=] with [=predicate=] `rdf:type` and the class [=IRI=] as [=object=] will be generated.
 
 <aside class="note">
 Mappings where the class [=IRI=] is not constant,
-but needs to be computed based on the contents of the database,
+but needs to be computed based on the contents of the logical source,
 can be achieved by defining a [=predicate-object map=] with predicate `rdf:type`
 and a non-constant [=object map=].
 </aside>

spec/section/output.md

@@ -17,24 +17,23 @@ RDF syntaxes and RDF APIs generally represent [=blank nodes=] with [=blank node
 
 ## The Generated RDF Triples of a Triples Map
 
+This subsection describes the process of <dfn data-lt="generated RDF triples">generating RDF triples</dfn> from a [=Triples Map=]. This process contributes [=RDF triples=] to the [=output dataset=]. Each generated triple MUST be placed into one or more graphs of the output dataset.
 
-This subsection describes the normative process by which [=RDF triples=] are generated from a [=Triples Map=]. This process contributes [=RDF triples=] to the [=output dataset=]. Each generated triple MUST be placed into one or more graphs of the output dataset.
-
-The generated RDF triples are determined by the following algorithm. [=RML Processors=] MAY employ alternative implementations to compute the generated [=RDF triples=], provided that the resulting output dataset is semantically equivalent to the one obtained by this algorithm.
+The [=generated RDF triples=] are determined by the following algorithm. [=RML Processors=] MAY employ alternative implementations to compute the generated [=RDF triples=], provided that the resulting output dataset is semantically equivalent to the one obtained by this algorithm.
 
 
 Let:
 
 - **sm** be the [=subject map=] of the [=Triples Map=].
-- **records** be the set of logical records obtained by evaluating the [=logical source=] of the [=Triples Map=] using its declared [=reference formulation=].
-- **classes** be the set of class [=IRIs=] defined in **sm** (via `rml:class`).
+- **iterations** be the set of [=logical iterations=] obtained by evaluating the [=logical source=] of the [=Triples Map=] using its declared [=reference formulation=].
+- **classes** be the set of [=class IRIs=] defined in **sm** (via `rml:class`).
 - **sgm** be the set of [=graph maps=] attached to **sm**.
 
-For each logical record **record** in **records**, apply the following steps:
+For each [=logical iteration=]  **iteration** in **iterations**, apply the following steps:
 
-1. Let [=subject=] be the [=RDF term=] resulting from applying **sm** to **record**.
-2. Let **subject_graphs** be the set of [=RDF term=] resulting from applying each graph map in **sgm** to **record**.
-3. For each class [=IRI=] in **classes**, add a triple to the [=output dataset=] as follows:
+1. Let [=subject=] be the [=generated RDF term=] resulting from applying **sm** to **iteration**.
+2. Let **subject_graphs** be the set of [=generated RDF terms=] resulting from applying each graph map in **sgm** to **iteration**.
+3. For each [=class IRI=] in **classes**, add a triple to the [=output dataset=] as follows:
 
    | Component | Value |
    |------------|--------|
@@ -45,10 +44,10 @@ For each logical record **record** in **records**, apply the following steps:
 
 4. For each [=predicate-object map=] of the Triples Map, apply the following steps:
 
-   - Let **predicates** be the set of [=RDF terms=] resulting from applying each predicate map of the predicate-object map to **record**.
-   - Let **objects** be the set of [=RDF terms=] resulting from applying each object map (excluding [=referencing object maps=]) to **record**.
+   - Let **predicates** be the set of [=generated RDF terms=] resulting from applying each predicate map of the predicate-object map to **iteration**.
+   - Let **objects** be the set of [=generated RDF terms=] resulting from applying each [=object map=] (excluding [=referencing object maps=]) to **iteration**.
    - Let **pogm** be the set of graph maps of the predicate-object map.
-   - Let **predicate_object_graphs** be the set of RDF terms resulting from applying each graph map in **pogm** to **record**.
+   - Let **predicate_object_graphs** be the set of [=generated RDF terms=] resulting from applying each [=graph map=] in **pogm** to **iteration**.
 
    For each possible combination `<predicate, object>`, where *predicate* ∈ **predicates** and *object* ∈ **objects**, add a triple to the output dataset as follows:
 
@@ -64,15 +63,15 @@ For each [=referencing object map=] of a [=predicate-object map=] in the [=Tripl
 
 - Let **psm** be the [=subject map=] of the [=parent Triples Map=] referenced by [=referencing object map=].
 - Let **pogm** be the set of [=graph maps=] of the [=predicate-object map=].
-- Let **joined_records** be the result of evaluating the [=join conditions=] defined by the [=referencing object map=], combining records from both the child and parent logical sources.
+- Let **joined_iterations** be the result of evaluating the [=join conditions=] defined by the [=referencing object map=], combining iterations from both the [=child logical source=] and [=parent logical sources=].
 
-For each pair `<child_record, parent_record>` in **joined_records**, apply the following steps:
+For each pair `<child_iteration, parent_iteration>` in **joined_iterations**, apply the following steps:
 
-1. Let **subject** be the [=RDF terms=] resulting from applying **sm** to **child_record**.
-2. Let **predicates** be the set of [=RDF terms=] resulting from applying each [=predicate map=] of the [=predicate-object map=] to **child_record**.
-3. Let **object** be the [=RDF terms=] resulting from applying **psm** to **parent_record**.
-4. Let **subject_graphs** be the set of RDF terms resulting from applying each graph map in **sgm** to **child_record**.
-5. Let **predicate_object_graphs** be the set of RDF terms resulting from applying each graph map in **pogm** to **child_record**.
+1. Let **subject** be the [=generated RDF term=] resulting from applying **sm** to **child_iteration**.
+2. Let **predicates** be the set of [=generated RDF terms=] resulting from applying each [=predicate map=] of the [=predicate-object map=] to **child_iteration**.
+3. Let **object** be the [=generated RDF term=] resulting from applying **psm** to **parent_iteration**.
+4. Let **subject_graphs** be the set of [=generated RDF terms=] resulting from applying each [=graph map=] in **sgm** to **child_iteration**.
+5. Let **predicate_object_graphs** be the set of [=generated RDF terms=] resulting from applying each graph map in **pogm** to **child_iteration**.
 
 For each *predicate* in **predicates**, add a triple to the output dataset as follows:
 
@@ -88,40 +87,40 @@ For each *predicate* in **predicates**, add a triple to the output dataset as fo
 
 “Add triples to the output dataset” is a process that takes the following inputs:
 
-| Input | Description                                     |
-|--------|-------------------------------------------------|
-| **Subject** | an [=IRI=], a [=URI=], [=blank node=], or empty |
-| **Predicate** | an [=IRI=], a [=URI=], or empty                 |
-| **Object** | an [=RDF term=] or empty                        |
-| **Target graphs** | a set of zero or more [=IRIs=]                  |
+| Input | Description               |
+|--------|---------------------------|
+| **Subject** | an [=IRI=], [=blank node=], or empty |
+| **Predicate** | an [=IRI=], or empty      |
+| **Object** | an [=RDF term=] or empty  |
+| **Target graphs** | a set of zero or more [=IRIs=] |
 
 Execute the following steps:
 
 1. If **Subject**, **Predicate**, or **Object** is empty, **abort** these steps.  
 2. Otherwise, generate an [=RDF triple=] `<Subject, Predicate, Object>`.  
 3. If the set of target graphs includes `rml:defaultGraph`, add the triple to the [=default graph=] of the [=output dataset=].  
 4. For each [=IRI=] in the set of target graphs not equal to `rml:defaultGraph`, add the triple to the [=named graph=] identified by that [=IRI=] in the [=output dataset=].  
-   - If the [=named graph=] does not yet exist, create it.  
-5. RDF graphs MUST NOT contain duplicate triples. Adding multiple identical triples to the same graph has the same effect as adding it once.  
-6. The scope of blank nodes is limited to the output dataset being generated.
+   - If the [=named graph=] does not yet exist, create it.
+
+RDF graphs MUST NOT contain duplicate triples. Adding multiple identical triples to the same graph has the same effect as adding it once. Also note the [[[#scope-of-blank-nodes]]].  
 
 ### Generated RDF Term of a Term Map
 
 
 A [=term map=] defines how an [=RDF term=] is generated from the evaluation of a [=logical iteration=] over a [=logical source=].  
-The result of evaluating a term map for a given logical record can be one of the following:
+The result of evaluating a term map for a given [=logical iteration=] can be one of the following:
 
-- **Empty**, if any referenced value of the [=term map=] evaluates to a null, empty or missing value (each data format defines it in [RML-IO-Registry](https://w3id.org/kg-construct/rml-io-registry/));  
-- **An [=RDF term=]**, when evaluation produces a valid [=RDF term=]according to the [=term generation rules=];  
-- **A data error**, when a valid RDF term cannot be produced.
+- **Empty**, if the [=expression evaluation result=] of the [=term map=] evaluates to a null, empty or missing value (each data format defines it in [RML-IO-Registry](https://w3id.org/kg-construct/rml-io-registry/));  
+- **An [=RDF term=]**, when evaluation produces a valid [=RDF term=] according to the [=term generation rules=];  
+- **A [=data error=]**, when a valid RDF term cannot be produced.
 
-The [=generated RDF term=] of a [=term map=] for a given logical record is determined as follows:
+The [=generated RDF term=] of a [=term map=] for a given [=logical iteration=] is determined as follows:
 
-1. If the term map is a **constant-valued term map**, then the generated RDF term is the term map’s constant value.
-2. If the term map is a **reference-valued term map**, then the generated RDF term is determined by evaluating the [=reference value=] expression over the logical record and applying the *term generation rules* to the resulting value.
-3. If the term map is a **template-valued term map**, then the generated RDF term is determined by evaluating the [=template value=] against the logical record and applying the *term generation rules* to the resulting value.
+1. If the term map is a [=constant-valued term map=], then the generated RDF term is the term map’s [=constant value=].
+2. If the term map is a [=reference-valued term map=], then the generated RDF term is determined by applying the [=term generation rules=] to its [=reference value=].
+3. If the term map is a [=template-valued term map=], then the generated RDF term is determined by applying the [=term generation rules=] to the [=template value=].
 
-The <dfn>term generation rules</dfn> define how a concrete RDF term is generated from a given value:
+The <dfn>term generation rules</dfn> define how a concrete RDF term is generated from each value from an [=expression evaluation result=]:
 
 1. **If the value is null, empty or missing**, then no RDF term is generated.
 
@@ -141,9 +140,9 @@ The <dfn>term generation rules</dfn> define how a concrete RDF term is generated
    - Return a blank node that is unique in the target graph.
 
 5. **If the term type is `rml:Literal`:**
-   - If the term map declares a [=language tag=], then return a literal with that language tag and the natural RDF lexical form corresponding to *value*.
-   - Otherwise, if the term map declares a non-empty [=datatype=] different from the natural RDF datatype corresponding to the value’s implicit datatype, then return an RDF literal with the specified datatype.
-   - Otherwise, return the natural RDF literal corresponding to *value*.
+   - If the term map declares a [=language map=], then evaluate the [=language map=] to obtain a [=language tag=] and return a literal with that [=language tag=] and the natural RDF lexical form corresponding to *value*.
+   - Otherwise, if the term map declares a [=datatype map=], then evaluate it to obtain a [=datatype-override RDF literal=] corresponding to *value* and the specified datatype.
+   - Otherwise, return the [=natural RDF literal=] corresponding to *value*.
 
 
 

spec/section/terminology.md

@@ -27,6 +27,11 @@ This section lists some terms normatively defined in [[RDF11-CONCEPTS]] and used
 - <dfn><a data-cite="RDF11-CONCEPTS#dfn-resource">resource</a></dfn>
 - <dfn><a data-cite="RDF11-CONCEPTS#dfn-subject">subject</a></dfn>
 
+## RDFS Terminology
+
+This section lists some terms normatively defined in [[RDF11-SCHEMA]] and used in RML:
+
+- <dfn><a data-cite="RDF11-schema#ch_class">RDFS class</a></dfn>
 
 # XML Schema Definition Language (XSD) Terminology