Relation


Definition: Relation
A relation is a semantic connection between a subject and an object. 

The connection has to be semantic

The connection must have a meaning.

If we only know that a subject is connected to an object, then this connection is meaningless.

A strange example would be the  'has nothing to do with' relation. This relation is however meaningful.

The relation is unidirectional

The relation is only a connection from a subject to an object, it does not imply any connection from object to subject.

There is no notion of an inverse relation.

Example

The haschild relation

Assume we have a family with a grandparent, a parent and a child.

The following relations hold:


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