10.1.5 Summary


A token is an indivisible textual unit which carries a meaning.


An identifier is any combination of English letters (a-z,A-Z), digits (0-9) and underscores ('_') where the first two characters are letters.

Identifiers are used for concept types, relations types, and names of individuals.


Concepts are enclosed in [square brackets]. They always have a concept type which is an identifier. They optionally have a referent, which must also be an identifier, optionally mixed with "super", "x_source", or "y_target". A concept can also have a nested graph or a value, such as an individual, both of which must be preceded by an equals sign '='.


Relations must be identifiers, must exist in the relation hierarchy, and are always dyadic.


A relation must have a dash ('-') on one side, and an arrow-head ('<-' or '->') on the other.

More than one relation

If a concept has two relations attached, it is possible to write it all on one line.

If a concept has more than two relations attached, one can split the graph over several lines.

Start by placing a dash ('-') after the concept which must have several relations attached. Then enter a newline.

Each relation that goes back to the head concept must be on a separate line, with commas after the concepts to indicate that one more is coming.

The string of relations can be ended by a semicolon. This is useful if you need to restart an earlier string. In that case, write a semicolon followed by a comma.


Next, we start what we really came for in this chapter: Entering CGs into our ontology.

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