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Is symmetric

Type(s): Association type

Subject Identifiers (1)

Internal Occurrences (1)

  • [No name]
    • Unary association used to mark association types as being symmetrical. Symmetric associations are associations like friend-of or neighbour-of where X friend-of Y implies that also Y friend-of X. In Topic Maps these are implemented as binary associations where the same role type is played by both topics, as follows: <pre> friend-of(X : friend, Y : friend) </pre> This way, the association only has to be stated once to be applicable in both directions. However, Ontopoly treats association types with just a single role type as unary associations. Therefore, it's necessary to state explicitly that these association types are symmetric, and that is done with this unary association. Usage: <pre> on:is-symmetric(friend-of : on:field-type) </pre>
Object id: 277