Adapt terminology to the multi-parent case

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

@@ -3925,9 +3925,9 @@ <h1 id="2-overview"><a name="Overview" href="#Overview">2</a>
 segments ending in a primitive property. This path points to the
 property holding the node identifier of the node in the hierarchy.</li>
 <li>The <code>ParentNavigationProperty</code> allows navigation to the
-instance representing the parent node. It MUST be a nullable single- or
-collection-valued navigation property path that addresses the entity
-type annotated with this term.</li>
+instance or instances representing the parent nodes. It MUST be a
+nullable single- or collection-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
@@ -3936,22 +3936,24 @@ <h1 id="2-overview"><a name="Overview" href="#Overview">2</a>
 <code>rolluprecursive</code></a>, and in <a
 href="#HierarchyFunctions">hierarchy functions</a>.</p>
 <p>A <em>node</em> is an instance of an entity type annotated with
-<code>RecursiveHierarchy</code>. It may have a <code>parent node</code>
-that is the target instance reached via the
-<code>ParentNavigationProperty</code>. A
-<code>recursive hierarchy</code> is a collection of such nodes with
+<code>RecursiveHierarchy</code> and a given qualifier. The same entity
+can be different nodes, given different qualifiers. A node may have one
+or more <em>parent nodes</em> that are the target instances reached via
+the <code>ParentNavigationProperty</code>. A <em>recursive
+hierarchy</em> for a given qualifier is a collection of such nodes with
 unique node identifiers and no cycles in the traversal of parent
 links.</p>
-<p>A node without parent node is a <em>root node</em>, a node is a
-<em>child node</em> of its parent node, a node without child nodes is a
-<em>leaf node</em>. Nodes with the same parent node are <em>sibling
-nodes</em> and so are root nodes. The <em>descendants</em> of a node are
-its child nodes, their child nodes, and so on, up to and including all
-leaf nodes that can be reached. A node together with its descendants
-forms a <em>sub-hierarchy</em> of the hierarchy. The <em>ancestors</em>
-of a node are its parent node, the parent of its parent node, and so on,
-up to and including a root node that can be reached. A recursive
-hierarchy can have one or more root nodes.</p>
+<p>A node without parent node or with null as parent node is a <em>root
+node</em>, a node is a <em>child node</em> of its parent nodes, a node
+without child nodes is a <em>leaf node</em>. Nodes with a common parent
+node are <em>sibling nodes</em> and so are root nodes. The
+<em>descendants</em> of a node are its child nodes, their child nodes,
+and so on, up to and including all leaf nodes that can be reached. A
+node together with its descendants forms a <em>sub-hierarchy</em> of the
+hierarchy. The <em>ancestors</em> of a node are its parent nodes, the
+parents of its parent nodes, and so on, up to and including root nodes
+that can be reached. A recursive hierarchy can have one or more root
+nodes.</p>
 <p>The term <code>UpNode</code> can be used in hierarchical result sets
 to associate with each instance one of its ancestors, which is again
 annotated with <code>UpNode</code> and so on until a path to the root is
@@ -3991,7 +3993,7 @@ <h1 id="2-overview"><a name="Overview" href="#Overview">2</a>
 <code>IncludeSelf</code> is true</li>
 <li><code>issibling</code> tests if the given entity and another entity
 (whose node identifier is given in a parameter <code>Other</code>) have
-the same parent node or both are roots, but are not the same</li>
+a common parent node or both are roots, but are not the same</li>
 <li><code>isleaf</code> tests if the given entity is without
 descendants.</li>
 </ul>

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

@@ -2364,13 +2364,13 @@ The term `LeveledHierarchy` MUST be applied with a qualifier that can be used to
 
 A recursive hierarchy organizes entities of a collection as nodes of one or more tree structures. This structure does not need to be as uniform as a leveled hierarchy. It is described by a complex term `RecursiveHierarchy` with these properties:
 - The `NodeProperty` contains a path with single-valued segments ending in a primitive property. This path points to the property holding the node identifier of the node in the hierarchy.
-- The `ParentNavigationProperty` allows navigation to the instance representing the parent node. It MUST be a nullable single- or collection-valued navigation property path that addresses the entity type annotated with this term.
+- The `ParentNavigationProperty` allows navigation to the instance or instances representing the parent nodes. It MUST be a nullable single- or collection-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).
 
-A _node_ is an instance of an entity type annotated with `RecursiveHierarchy`. It may have a `parent node` that is the target instance reached via the `ParentNavigationProperty`. A `recursive hierarchy` is a collection of such nodes with unique node identifiers and no cycles in the traversal of parent links.
+A _node_ is an instance of an entity type annotated with `RecursiveHierarchy` and a given qualifier. The same entity can be different nodes, given different qualifiers. A node may have one or more _parent nodes_ that are the target instances reached via the `ParentNavigationProperty`. A _recursive hierarchy_ for a given qualifier is a collection of such nodes with unique node identifiers and no cycles in the traversal of parent links.
 
-A node without parent node is a _root node_, a node is a _child node_ of its parent node, a node without child nodes is a _leaf node_. Nodes with the same parent node are _sibling nodes_ and so are root nodes. The _descendants_ of a node are its child nodes, their child nodes, and so on, up to and including all leaf nodes that can be reached. A node together with its descendants forms a _sub-hierarchy_ of the hierarchy. The _ancestors_ of a node are its parent node, the parent of its parent node, and so on, up to and including a root node that can be reached. A recursive hierarchy can have one or more root nodes.
+A node without parent node or with null as parent node is a _root node_, a node is a _child node_ of its parent nodes, a node without child nodes is a _leaf node_. Nodes with a common parent node are _sibling nodes_ and so are root nodes. The _descendants_ of a node are its child nodes, their child nodes, and so on, up to and including all leaf nodes that can be reached. A node together with its descendants forms a _sub-hierarchy_ of the hierarchy. The _ancestors_ of a node are its parent nodes, the parents of its parent nodes, and so on, up to and including root nodes that can be reached. A recursive hierarchy can have one or more root nodes.
 
 The term `UpNode` can be used in hierarchical result sets to associate with each instance one of its ancestors, which is again annotated with `UpNode` and so on until a path to the root is constructed.
 
@@ -2386,7 +2386,7 @@ The following functions are defined:
 - `isroot` tests if the given entity is a root of the hierarchy
 - `isdescendant` tests if the given entity is a descendant of an ancestor node (whose node identifier is given in a parameter `Ancestor`) with a maximum distance `MaxDistance`, or equals the ancestor if `IncludeSelf` is true
 - `isancestor` tests if the given entity is an ancestor of a descendant node (whose node identifier is given in a parameter `Descendant`) with a maximum distance `MaxDistance`, or equals the descendant if `IncludeSelf` is true
-- `issibling` tests if the given entity and another entity (whose node identifier is given in a parameter `Other`) have the same parent node or both are roots, but are not the same
+- `issibling` tests if the given entity and another entity (whose node identifier is given in a parameter `Other`) have a common parent node or both are roots, but are not the same
 - `isleaf` tests if the given entity is without descendants.
 
 ### <a name="HierarchyExamples" href="#HierarchyExamples">5.5.3</a> Hierarchy Examples

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

@@ -167,13 +167,13 @@ The term `LeveledHierarchy` MUST be applied with a qualifier that can be used to
 
 A recursive hierarchy organizes entities of a collection as nodes of one or more tree structures. This structure does not need to be as uniform as a leveled hierarchy. It is described by a complex term `RecursiveHierarchy` with these properties:
 - The `NodeProperty` contains a path with single-valued segments ending in a primitive property. This path points to the property holding the node identifier of the node in the hierarchy.
-- The `ParentNavigationProperty` allows navigation to the instance representing the parent node. It MUST be a nullable single- or collection-valued navigation property path that addresses the entity type annotated with this term.
+- The `ParentNavigationProperty` allows navigation to the instance or instances representing the parent nodes. It MUST be a nullable single- or collection-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).
 
-A _node_ is an instance of an entity type annotated with `RecursiveHierarchy`. It may have a `parent node` that is the target instance reached via the `ParentNavigationProperty`. A `recursive hierarchy` is a collection of such nodes with unique node identifiers and no cycles in the traversal of parent links.
+A _node_ is an instance of an entity type annotated with `RecursiveHierarchy` and a given qualifier. The same entity can be different nodes, given different qualifiers. A node may have one or more _parent nodes_ that are the target instances reached via the `ParentNavigationProperty`. A _recursive hierarchy_ for a given qualifier is a collection of such nodes with unique node identifiers and no cycles in the traversal of parent links.
 
-A node without parent node is a _root node_, a node is a _child node_ of its parent node, a node without child nodes is a _leaf node_. Nodes with the same parent node are _sibling nodes_ and so are root nodes. The _descendants_ of a node are its child nodes, their child nodes, and so on, up to and including all leaf nodes that can be reached. A node together with its descendants forms a _sub-hierarchy_ of the hierarchy. The _ancestors_ of a node are its parent node, the parent of its parent node, and so on, up to and including a root node that can be reached. A recursive hierarchy can have one or more root nodes.
+A node without parent node or with null as parent node is a _root node_, a node is a _child node_ of its parent nodes, a node without child nodes is a _leaf node_. Nodes with a common parent node are _sibling nodes_ and so are root nodes. The _descendants_ of a node are its child nodes, their child nodes, and so on, up to and including all leaf nodes that can be reached. A node together with its descendants forms a _sub-hierarchy_ of the hierarchy. The _ancestors_ of a node are its parent nodes, the parents of its parent nodes, and so on, up to and including root nodes that can be reached. A recursive hierarchy can have one or more root nodes.
 
 The term `UpNode` can be used in hierarchical result sets to associate with each instance one of its ancestors, which is again annotated with `UpNode` and so on until a path to the root is constructed.
 
@@ -189,7 +189,7 @@ The following functions are defined:
 - `isroot` tests if the given entity is a root of the hierarchy
 - `isdescendant` tests if the given entity is a descendant of an ancestor node (whose node identifier is given in a parameter `Ancestor`) with a maximum distance `MaxDistance`, or equals the ancestor if `IncludeSelf` is true
 - `isancestor` tests if the given entity is an ancestor of a descendant node (whose node identifier is given in a parameter `Descendant`) with a maximum distance `MaxDistance`, or equals the descendant if `IncludeSelf` is true
-- `issibling` tests if the given entity and another entity (whose node identifier is given in a parameter `Other`) have the same parent node or both are roots, but are not the same
+- `issibling` tests if the given entity and another entity (whose node identifier is given in a parameter `Other`) have a common parent node or both are roots, but are not the same
 - `isleaf` tests if the given entity is without descendants.
 
 ### ##subsubsec Hierarchy Examples