# Category Theory

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Category Theory is the mathematical theory of structure-respecting transformations. A

*category* consists of

*arrows* (or

*morphisms*) between

*objects*. For example, we can form a category by taking partially ordered sets as the objects and order-respecting mappings as the arrows. Using general category-theoretical notions, we can then determine the meaning of such concepts as the

*product* of two partially ordered sets. Such general notions are typically defined by

*universal properties*, which determine the result uniquely (up to isomorphism).

For further online information, see: *A Gentle Introduction to Category Theory - the calculational approach*, by Maarten Fokkinga, http://www.cs.utwente.nl/~fokkinga/mmf92b.ps