Examples of org.semanticweb.owlapi.reasoner.Node

Represents a node (set) of entities. The entities in a node are equivalent to each other.

Nodes in hierarchies

In the OWL API, a reasoner treats a class hierarchy, an object property hierarchy or a data property hierarchy as a hierarchy (directed acyclic graph - DAG) of {@code Nodes}. Each node contains entities that are equivalent to each other. A hierarchy contains a top node, which is the ancestor of all nodes in the hierarchy, and a bottom node In a class hierarchy, the nodes contain {@code OWLClass}objects. The top node contains {@code owl:Thing} (and any other named classesthat are equivalent to {@code owl:Thing}). The bottom node contains {@code owl:Nothing} (and any other named classes that are equivalent to{@code owl:Nothing} - these classes are unsatisfiable In an objectproperty hierarchy, the nodes contain {@code OWLObjectProperty} objects. Thetop node contains {@code owl:topObjectProperty} (and any other named objectproperties that are equivalent to {@code owl:topObjectProperty}). The bottom node contains {@code owl:bottomObjectProperty} (and any other named objectproperties that are equivalent to {@code owl:bottomObjectProperty}).
In a data property hierarchy, the nodes contain {@code OWLDataProperty}objects. The top node contains {@code owl:topDataProperty} (and any otherdata properties that are equivalent to {@code owl:topDataProperty}). The bottom node contains {@code owl:bottomDataProperty} (and any other dataproperties that are equivalent to {@code owl:bottomDataProperty}).

Class Hierarchy Example

The figure below shows an example class hierarchy. Each box in the hierarchy represents a {@code Node}. In this case the top node contains {@code owl:Thing} and the bottom node contains{@code owl:Nothing} because the nodes in the hierarchy are {@code OWLClass}nodes. In this case, class {@code G} is equivalent to {@code owl:Thing} so itappears as an entity in the top node. Similarly, class {@code K} isunsatisfiable, so it is equivalent to {@code owl:Nothing} and thereforeappears in the bottom node containing {@code owl:Nothing}.
hierarchy

@author Matthew Horridge, The University of Manchester, InformationManagement Group @since 3.0.0 @param < E> the type of elements represented in the Node