polyhierarchical classification
polyhierarchical classification
A hierarchy in which each node has one or more parents.
Notes
The subtype relationships of SNOMED CT create a polyhierarchical classification.
A polyhierarchical classification can be represented as a graph in which each node has a one or more directed links to or from other nodes.
A node in a polyhierarchical classification cannot be a descendant of itself, which means the hierarchy must not contain cyclic relationships. This type of hierarchy is therefore known as a directed acyclic graph.
Examples
The diagram below shows a polyhierarchy. Each node has one or more parent node so there can be multiple paths from a node to the top (or root) of the hierarchy. For example from node V the paths include the following:
V→N→F→B→A
V→N→F→C→A
V→G→C→A
Alternatives
Polyhierarchy
Related Links
Statistical classification
Monohierarchical classification
Subtype classification
Directed acyclic graph
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