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Syntax: (tell <simple-predication>) ::=
        (tell [<relation-name> <instance> <value>])

The operator TELL makes it possible to assign new
values to the instances for certain relations and
to change the knowledge base in this way.
Only a simple two-argument-predication can follow after
the operator TELL, i.e it is possible to connect a value
to a part or characteristic of an instance and in this
way change the knowledge base. The pre-
dication which follows after TELL has to be full
instanciated, there must not be any anonymus-
variable instead of a value in this place.
The operator TELL returns T, if the operation
is executed. NIL will be returned, if the pre-
dication is already known, therefore both of
the statements will be tested internally with
the function EQUAL. If the test is positive, then
NIL will be returned.

Example: >(tell [place Buckingham-palace London])

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