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Categories and Relations - Datamaster User's Manual (Site not responding. Last check: 2007-10-19) |
 | | Category structures are often illustrated using diagrams: morphisms are drawn as arrows, and composition is shown as two arrow placed with the head of the first joined to the tail of the second. |
 | | In the category of sets, a table on A, B may be viewed as a listing ('tabulation'), without repetition, of the instances of a relation from A to B. The categorical notion of relations as applied to sets is the same as the usual extensional notion of relations on sets. |
 | | A primitive in the theory of categories is a predicate that asserts one of: two elements are equal, an element is the source of another element, an element is the target of another element, or an element is the composition of two other elements. |
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