@GeraldKrause's suggestions

docs/odata-data-aggregation-ext/odata-data-aggregation-ext.html

@@ -2565,11 +2565,11 @@ <h3 id="552-recursive-hierarchy"><a name="RecursiveHierarchy" href="#RecursiveHi
 <p>A recursive hierarchy is defined on a collection of entities by</p>
 <ul>
 <li>associating with every entity zero or more entities from the same collection, called its <em>parents</em>, and</li>
-<li>identifying entities that are part of the recursive hierarchy through a single primitive property called the <em>node identifier</em>. The entities in the hierarchy are called <em>nodes</em>.</li>
+<li>identifying entities that are part of the recursive hierarchy through a single primitive non-null value called the <em>node identifier</em>. These entities that are part of the hierarchy are called <em>nodes</em>.</li>
 </ul>
 <p>The recursive hierarchy is described in the model by an annotation of the entity type with the complex term <code>RecursiveHierarchy</code> with these properties:</p>
 <ul>
-<li>The <code>NodeProperty</code> allows identifying a node in the hierarchy. It MUST be a path with single-valued segments ending in a primitive property. This property holds the node identifier of the node in the hierarchy. Entities for which this path evaluates to null are not nodes of the hierarchy.</li>
+<li>The <code>NodeProperty</code> allows identifying a node in the hierarchy. It MUST be a path with single-valued segments ending in a primitive property. This property holds the node identifier of the node in the hierarchy and null if the entity is not in the hierarchy.</li>
 <li>The <code>ParentNavigationProperty</code> allows navigation to the instance or instances representing the parent nodes. It MUST be a collection-valued or nullable single-valued navigation property path that addresses the entity type annotated with this term.</li>
 </ul>
 <p>The term <code>RecursiveHierarchy</code> can only be applied to entity types, and MUST be applied with a qualifier, which is used to reference the hierarchy in transformations operating on recursive hierarchies, in <a href="#Groupingwithrolluprecursive">grouping with <code>rolluprecursive</code></a>, and in <a href="#HierarchyFunctions">hierarchy functions</a>. The same entity can serve as nodes in different recursive hierarchies, given different qualifiers.</p>
@@ -2750,15 +2750,15 @@ <h2 id="56-functions-on-aggregated-entities"><a name="FunctionsonAggregatedEntit
 <hr />
 <h1 id="6-hierarchical-transformations"><a name="HierarchicalTransformations" href="#HierarchicalTransformations">6 Hierarchical Transformations</a></h1>
 <p>The transformations and the <code>rolluprecursive</code> operator defined in this section are called hierarchical, because they make use of a recursive hierarchy and are defined in terms of hierarchy functions introduced in the previous section.</p>
-<p>With the exceptions of <code>traverse</code> and <code>rolluprecursive</code> with <code>traverse</code> as fourth parameter, the hierarchical transformations do not define an order on the output set. An order can be reinstated by a subsequent <code>orderby</code> or <code>traverse</code> transformation or a <code>$orderby</code>.</p>
+<p>With the exceptions of <code>traverse</code> and <code>rolluprecursive</code> whose fourth parameter ends with <code>traverse</code>, the hierarchical transformations do not define an order on the output set. An order can be reinstated by a subsequent <code>orderby</code> or <code>traverse</code> transformation or a <code>$orderby</code>.</p>
 <p>The algorithmic descriptions of the transformations make use of a <em>union</em> of collections, this is defined as an unordered collection containing the items from all these collections and from which duplicates have been removed.</p>
 <p>The notation <span class="math inline">\(u[t]\)</span> is used to denote the value of a property <span class="math inline">\(t\)</span>, possibly preceded by a type-cast segment, in an instance <span class="math inline">\(u\)</span>. It is also used to denote the value of a single-valued data aggregation path <span class="math inline">\(t\)</span>, evaluated relative to <span class="math inline">\(u\)</span>. The value of a collection-valued <a href="#DataAggregationPath">data aggregation path</a> is denoted in the <a href="#EvaluationofDataAggregationPaths"><span class="math inline">\(\Gamma\)</span> notation</a> by <span class="math inline">\(γ(u,t)\)</span>.</p>
 <p>The notations introduced here are used throughout the following subsections.</p>
 <h2 id="61-common-parameters-for-hierarchical-transformations"><a name="CommonParametersforHierarchicalTransformations" href="#CommonParametersforHierarchicalTransformations">6.1 Common Parameters for Hierarchical Transformations</a></h2>
 <p>The parameter lists defined in the following subsections have three mandatory parameters in common.</p>
 <p>The recursive hierarchy is defined by a parameter pair <span class="math inline">\((H,Q)\)</span>, where <span class="math inline">\(H\)</span> and <span class="math inline">\(Q\)</span> MUST be specified as the first and second parameter. Here, <span class="math inline">\(H\)</span> MUST be an expression of type <code>Collection(Edm.EntityType)</code> starting with <code>$root</code> that has no multiple occurrences of the same entity. <span class="math inline">\(H\)</span> identifies the collection of node entities forming a recursive hierarchy based on an annotation of their common entity type with term <code>RecursiveHierarchy</code> with a <code>Qualifier</code> attribute whose value MUST be provided in <span class="math inline">\(Q\)</span>. The property paths referenced by <code>NodeProperty</code> and <code>ParentNavigationProperty</code> in the <code>RecursiveHierarchy</code> annotation must be evaluable for the nodes in the recursive hierarchy, otherwise the service MUST reject the request. The <code>NodeProperty</code> is denoted by <span class="math inline">\(q\)</span> in this section.</p>
 <p>The third parameter MUST be a data aggregation path <span class="math inline">\(p\)</span> with single- or collection-valued segments whose last segment MUST be a primitive property. The node identifier(s) of an instance <span class="math inline">\(u\)</span> in the input set are the primitive values in <span class="math inline">\(γ(u,p)\)</span>, they are reached via <span class="math inline">\(p\)</span> starting from <span class="math inline">\(u\)</span>. Let <span class="math inline">\(p=p_1/…/p_k/r\)</span> with <span class="math inline">\(k≥0\)</span> be the concatenation where each sub-path <span class="math inline">\(p_1,…,p_k\)</span> consists of a collection-valued segment that is preceded by zero or more single-valued segments, and either <span class="math inline">\(r\)</span> consists of one or more single-valued segments or <span class="math inline">\(k≥1\)</span> and <span class="math inline">\({}/r\)</span> is absent. Each segment can be prefixed with a type cast.</p>
-<p>Some parameter lists allow as optional fourth or fifth parameter a non-empty sequence <span class="math inline">\(S\)</span> of transformations. The transformations sequence <span class="math inline">\(S\)</span> will be applied to the node collection <span class="math inline">\(H\)</span>, it MUST consist of transformations listed in <a href="#TransformationsProducingaSubset">section 3.3</a> or <a href="#HierarchicalTransformationsProducingaSubset">section 6.2</a> or service-defined bound functions whose output set is a subset of their input set.</p>
+<p>Some parameter lists allow as optional fourth or fifth parameter a non-empty sequence <span class="math inline">\(S\)</span> of transformations. The transformations sequence <span class="math inline">\(S\)</span> will be applied to the node collection <span class="math inline">\(H\)</span>. It MUST consist of transformations listed in <a href="#TransformationsProducingaSubset">section 3.3</a> or <a href="#HierarchicalTransformationsProducingaSubset">section 6.2</a> or service-defined bound functions whose output set is a subset of their input set.</p>
 <h2 id="62-hierarchical-transformations-producing-a-subset"><a name="HierarchicalTransformationsProducingaSubset" href="#HierarchicalTransformationsProducingaSubset">6.2 Hierarchical Transformations Producing a Subset</a></h2>
 <p>These transformations produce an output set that consists of certain instances from their input set, possibly with repetitions or in a different order.</p>
 <h3 id="621-transformations-ancestors-and-descendants"><a name="Transformationsancestorsanddescendants" href="#Transformationsancestorsanddescendants">6.2.1 Transformations <code>ancestors</code> and <code>descendants</code></a></h3>

docs/odata-data-aggregation-ext/odata-data-aggregation-ext.md

@@ -2447,10 +2447,10 @@ The term `LeveledHierarchy` MUST be applied with a qualifier that can be used to
 
 A recursive hierarchy is defined on a collection of entities by
 - associating with every entity zero or more entities from the same collection, called its _parents_, and
-- identifying entities that are part of the recursive hierarchy through a single primitive property called the _node identifier_. The entities in the hierarchy are called _nodes_.
+- identifying entities that are part of the recursive hierarchy through a single primitive non-null value called the _node identifier_. These entities that are part of the hierarchy are called _nodes_.
 
 The recursive hierarchy is described in the model by an annotation of the entity type with the complex term `RecursiveHierarchy` with these properties:
-- The `NodeProperty` allows identifying a node in the hierarchy. It MUST be a path with single-valued segments ending in a primitive property. This property holds the node identifier of the node in the hierarchy. Entities for which this path evaluates to null are not nodes of the hierarchy.
+- The `NodeProperty` allows identifying a node in the hierarchy. It MUST be a path with single-valued segments ending in a primitive property. This property holds the node identifier of the node in the hierarchy and null if the entity is not in the hierarchy.
 - The `ParentNavigationProperty` allows navigation to the instance or instances representing the parent nodes. It MUST be a collection-valued or nullable single-valued navigation property path that addresses the entity type annotated with this term.
 
 The term `RecursiveHierarchy` can only be applied to entity types, and MUST be applied with a qualifier, which is used to reference the hierarchy in transformations operating on recursive hierarchies, in [grouping with `rolluprecursive`](#Groupingwithrolluprecursive), and in [hierarchy functions](#HierarchyFunctions). The same entity can serve as nodes in different recursive hierarchies, given different qualifiers.
@@ -2672,7 +2672,7 @@ Example 59: assume the product is an implicit input for a function bound to a co
 
 The transformations and the `rolluprecursive` operator defined in this section are called hierarchical, because they make use of a recursive hierarchy and are defined in terms of hierarchy functions introduced in the previous section.
 
-With the exceptions of `traverse` and `rolluprecursive` with `traverse` as fourth parameter, the hierarchical transformations do not define an order on the output set. An order can be reinstated by a subsequent `orderby` or `traverse` transformation or a `$orderby`.
+With the exceptions of `traverse` and `rolluprecursive` whose fourth parameter ends with `traverse`, the hierarchical transformations do not define an order on the output set. An order can be reinstated by a subsequent `orderby` or `traverse` transformation or a `$orderby`.
 
 The algorithmic descriptions of the transformations make use of a _union_ of collections, this is defined as an unordered collection containing the items from all these collections and from which duplicates have been removed.
 
@@ -2688,7 +2688,7 @@ The recursive hierarchy is defined by a parameter pair $(H,Q)$, where $H$ and $Q
 
 The third parameter MUST be a data aggregation path $p$ with single- or collection-valued segments whose last segment MUST be a primitive property. The node identifier(s) of an instance $u$ in the input set are the primitive values in $γ(u,p)$, they are reached via $p$ starting from $u$. Let $p=p_1/…/p_k/r$ with $k≥0$ be the concatenation where each sub-path $p_1,…,p_k$ consists of a collection-valued segment that is preceded by zero or more single-valued segments, and either $r$ consists of one or more single-valued segments or $k≥1$ and ${}/r$ is absent. Each segment can be prefixed with a type cast.
 
-Some parameter lists allow as optional fourth or fifth parameter a non-empty sequence $S$ of transformations. The transformations sequence $S$ will be applied to the node collection $H$, it MUST consist of transformations listed in [section 3.3](#TransformationsProducingaSubset) or [section 6.2](#HierarchicalTransformationsProducingaSubset) or service-defined bound functions whose output set is a subset of their input set.
+Some parameter lists allow as optional fourth or fifth parameter a non-empty sequence $S$ of transformations. The transformations sequence $S$ will be applied to the node collection $H$. It MUST consist of transformations listed in [section 3.3](#TransformationsProducingaSubset) or [section 6.2](#HierarchicalTransformationsProducingaSubset) or service-defined bound functions whose output set is a subset of their input set.
 
 ## <a name="HierarchicalTransformationsProducingaSubset" href="#HierarchicalTransformationsProducingaSubset">6.2 Hierarchical Transformations Producing a Subset</a>
 

odata-data-aggregation-ext/5 Vocabulary for Data Aggregation.md

@@ -176,10 +176,10 @@ The term `LeveledHierarchy` MUST be applied with a qualifier that can be used to
 
 A recursive hierarchy is defined on a collection of entities by
 - associating with every entity zero or more entities from the same collection, called its _parents_, and
-- identifying entities that are part of the recursive hierarchy through a single primitive property called the _node identifier_. The entities in the hierarchy are called _nodes_.
+- identifying entities that are part of the recursive hierarchy through a single primitive non-null value called the _node identifier_. These entities that are part of the hierarchy are called _nodes_.
 
 The recursive hierarchy is described in the model by an annotation of the entity type with the complex term `RecursiveHierarchy` with these properties:
-- The `NodeProperty` allows identifying a node in the hierarchy. It MUST be a path with single-valued segments ending in a primitive property. This property holds the node identifier of the node in the hierarchy. Entities for which this path evaluates to null are not nodes of the hierarchy.
+- The `NodeProperty` allows identifying a node in the hierarchy. It MUST be a path with single-valued segments ending in a primitive property. This property holds the node identifier of the node in the hierarchy and null if the entity is not in the hierarchy.
 - The `ParentNavigationProperty` allows navigation to the instance or instances representing the parent nodes. It MUST be a collection-valued or nullable single-valued navigation property path that addresses the entity type annotated with this term.
 
 The term `RecursiveHierarchy` can only be applied to entity types, and MUST be applied with a qualifier, which is used to reference the hierarchy in transformations operating on recursive hierarchies, in [grouping with `rolluprecursive`](#Groupingwithrolluprecursive), and in [hierarchy functions](#HierarchyFunctions). The same entity can serve as nodes in different recursive hierarchies, given different qualifiers.

odata-data-aggregation-ext/6 Hierarchical Transformations.md

@@ -4,7 +4,7 @@
 
 The transformations and the `rolluprecursive` operator defined in this section are called hierarchical, because they make use of a recursive hierarchy and are defined in terms of hierarchy functions introduced in the previous section.
 
-With the exceptions of `traverse` and `rolluprecursive` with `traverse` as fourth parameter, the hierarchical transformations do not define an order on the output set. An order can be reinstated by a subsequent `orderby` or `traverse` transformation or a `$orderby`.
+With the exceptions of `traverse` and `rolluprecursive` whose fourth parameter ends with `traverse`, the hierarchical transformations do not define an order on the output set. An order can be reinstated by a subsequent `orderby` or `traverse` transformation or a `$orderby`.
 
 The algorithmic descriptions of the transformations make use of a _union_ of collections, this is defined as an unordered collection containing the items from all these collections and from which duplicates have been removed.
 
@@ -20,7 +20,7 @@ The recursive hierarchy is defined by a parameter pair $(H,Q)$, where $H$ and $Q
 
 The third parameter MUST be a data aggregation path $p$ with single- or collection-valued segments whose last segment MUST be a primitive property. The node identifier(s) of an instance $u$ in the input set are the primitive values in $γ(u,p)$, they are reached via $p$ starting from $u$. Let $p=p_1/…/p_k/r$ with $k≥0$ be the concatenation where each sub-path $p_1,…,p_k$ consists of a collection-valued segment that is preceded by zero or more single-valued segments, and either $r$ consists of one or more single-valued segments or $k≥1$ and ${}/r$ is absent. Each segment can be prefixed with a type cast.
 
-Some parameter lists allow as optional fourth or fifth parameter a non-empty sequence $S$ of transformations. The transformations sequence $S$ will be applied to the node collection $H$, it MUST consist of transformations listed in [section ##TransformationsProducingaSubset] or [section ##HierarchicalTransformationsProducingaSubset] or service-defined bound functions whose output set is a subset of their input set.
+Some parameter lists allow as optional fourth or fifth parameter a non-empty sequence $S$ of transformations. The transformations sequence $S$ will be applied to the node collection $H$. It MUST consist of transformations listed in [section ##TransformationsProducingaSubset] or [section ##HierarchicalTransformationsProducingaSubset] or service-defined bound functions whose output set is a subset of their input set.
 
 ## ##subsec Hierarchical Transformations Producing a Subset