External Binary Operations
An external binary operation is a binary function from K × S to S. This differs from a binary operation in the strict sense in that K need not be S; its elements come from outside.
An example of an external binary operation is scalar multiplication in linear algebra. Here K is a field and S is a vector space over that field.
An external binary operation may alternatively be viewed as an action; K is acting on S.
Note that the dot product of two vectors is not a binary operation, external or otherwise, as it maps from S× S to K, where K is a field and S is a vector space over K.
Read more about this topic: Binary Operation
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