252 13 Local, Global and Glocal Knowledge Representation
ImplicationLink EvaluationLink eat ListLink $X aan, InheritanceLink $X sick
or
ForAllLink $X, $Y, $2 ExtensionalEquivalenceLink EquivalenceLink $Z EvaluationLink + ListLink $X $Y EquivalenceLink $Z EvaluationLink + ListLink $Y $X
Note, the latter is given as an extensional equivalence because it’s a pure mathematical equiv- alence. This is not the only case of pure extensional equivalence, but it’s an important one.
13.3.4 Temporal Links
There are also temporal versions of these links, such as
PredictiveImplicationLink PredictiveAttractionLink SequentialANDLink SimultaneousANDLink
which combine logical relation between the argument with temporal relation between their arguments. For instance, we might say PredictivelImplicationLink
PredicateNode: Jumpoffcliff PredicateNode: Dead
or including arguments,
PredictiveImplicationLink EvaluationLink JumpOffCliff $x EvaluationLink Dead $X
The former version, without variable arguments given, shows the possibility of using higher- order logical links to join predicates without any explicit variables. Via using this format exclu- sively, one could avoid VariableAtoms entirely, using only higher-order functions in the manner
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