SysML1.0:

Connectors can be typed by association classes that are stereotyped by Block (association blocks, see Section 8.3.2.7, “ParticipantProperty”). These connectors specify instances (links) of the association block that exist due to instantiation of the block owning or inheriting the connector. The value of a connector property on an instance of a block will be exactly those link objects that are instances of the association block typing the connector referred to by the connector property.

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