# ExtensionalSimilarityLink

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A type of Link used in OpenCog to define extensional implication.

For more information, see this page

## PLN Semantics

In PLN the ExtensionalSimilarityLink between 2 concepts is defined as ratio between the common properties (or elements) of two nodes and the total properties (or elements) of these nodes, i.e.,

${\displaystyle \operatorname {sim} (A,B)={\frac {P(A\wedge B)}{P(A\vee B)}}}$

where ${\displaystyle \wedge }$ denotes the fuzzy intersection. The TV of the similarity of A and B can also be seen as the TV of concept ${\displaystyle A\wedge B}$ in the context ${\displaystyle A\vee B}$ as explained in this thread [1]