A key concept of category theory is that of representable object (or representation, or universal element). This concept can be defined in both element style and naturality style—the equivalence of the two definitions follows from the Yoneda Lemma. So by describing something as a representable object, we automatically obtain both an element-style and a naturality-style description.
KeywordsUnique Functor Ordinary Category Unique Isomorphism Faithful Functor Family Construction
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