A "semantic" assertion about a relationship between a subject entity and a target entity, literal or compound expression as represented by an unnamed blank node ("bnode"). A "semantic" assertion about a relationship between a subject entity and a target entity, literal or compound expression as represented by an unnamed blank node ("bnode"). the subject of the association statement. subject must reference an Entity - i.e. a class, predicate and/or individual. The predicate of the association statement. In the OWL DL environment, predicates must reference instances of ObjectProperty, DataProperty and DataTypeProperty. The target (object) of the association statement. A target may be a reference to an entity, an external resource URI, a literal or a compound expression (bnode) or a set of targets. Additional tag/value attributes that qualify the association statement itself, vs the subject. The code system version that is making this assertion. A code system version makes an assertion when (a) it contains the assertion, (b) it imports a code system version that contains the assertion or (c) the assertion is inferred from other assertions. The code system version that actually contains this assertion. If absent, it is the same resource as assertedBy. The source our the statement. This attribute exists specifically to allow a reasoner / reasoning algorithm reference to be added to statements that are inferred vs. asserted. Detail about the provenance and history of the statement(s) from which this particular association is derived. This attribute will only be present in CTS₂ service implementations that support the statements model. The unique identifier of the association instance. While the update mechanism of the CTS₂ specifications requires that all Changeable elements have unique identifiers, the rules and mechanism for assigning unique identifiers to statements and associations are non-trivial. At the moment, the CTS₂ specification remains silent when it comes to arriving at how this identifier is generated except to note that, if two service implementations do not generate the same unique identifier for the same assertion, then the prevImage element in Changeable becomes the only way to identify which Association instance is being updated or deleted. how this association was derived. ASSERTED takes precedence over DERIVED , meaning that an assertion that is both asserted and derived is marked as asserted. The derivation of a given statement - whether it is directly asserted by the source, is derived by the application of a reasoner or is unknown because the reasoner or source does not supply such information. The statement was explicitly asserted by the asserting code system version. The statement was \emph{not} asserted by the code system version, but was logically inferred by the application of one ormore reasoning algorithms to other statements within the code system version. A representation of a component of a code system or ontology in a specified format and syntax. The language and syntax of the representation fragment The actual representation A Association read from a service instance. PSM A directory of Association resources that meet a specified criteria. A synopsis of an Association along with information about how to access the complete resource. The subject of the association statement. subject must reference an Entity - i.e. a class, predicate and/or individual. The predicate of the association statement. In the OWL DL environment, predicates must reference instances of ObjectProperty, DataProperty and DataTypeProperty. The target (object) of the association statement. A target may be a reference to an entity, an external resource URI, a literal or a compound expression (bnode) or a set of targets. The code system version that is making this assertion. A code system version makes an assertion when (a) it contains the assertion, (b) it imports a code system version that contains the assertion or (c) the assertion is inferred from other assertions. A collection of complete Association resources that meet a specified criteria. An instance of Association that meets a specified filter criteria. An augmented rendering of a set of Associations where the linkage between subject and target nodes has been normalized for easier traversal. An indicator that states whether the graph represents a graph at which the focus is in the subject role, the target role or both. Indicates that graph is based the graph focus in the source role - the graph is drawn from source to target with the source at the root. Indicates that graph is based the graph focus in the target role - the graph is drawn from target source with the source at the bottom. Indicates that graph is based the graph focus in both the source and the target role - the graph represents all associations in which the focus is either in the source or target role. Identifies the root of an association graph The focus on the graph is contained in focusEntity The focus of the graph is on the TOP or "universe" node The focus of the graph is on the BOTTOM or empty node The summary of an association as represented in a flattened graph structure. The URI, name and a designation for the EntityReference represented by this node. nodeEntity represents the association subject when direction is SOURCE_TO_TARGET and (one of the) targets when direction is TARGET_TO_SOURCE. The integer that corresponds to the particular EntityReference in nodeEntity. Every instance of the same EntityReference will be represented by the same nodeNumber. There will be graph node for every source predicate target combination in the association, with multiple GraphNodes being generated for targets that are of type set or BNode. An indicator whether nodeEntity plays a source or a target role in the accompanying AssociationDirectory instance An integer that represents the next graph node that is reached by traversing the specified predicate in the specified direction. This number will only be present if the result of traversing predicate results in an EntityReference. Target nodes of type ResourceReference or Literal will not be assigned node numbers. Note that each EntityReference target of a nested BNODE will be represented by a different GraphNode.