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Definition. Generalized element [math-0010]

Let E\mathcal{E} be a category, and let AA be an object of E\mathcal{E} . A generalized element of AA is simply a map in E\mathcal{E} with codomain AA .

A generalized element x:SAx : S \to A is shape SS or SS -element of AA .

When S=1S = 1 (the terminal) then SS -elements are called global elements.

Global elements can be very boring, for example in the category of groups.

The language of generalized elements is the internal language of the category. For example, let E\mathcal{E} be a category with finite products. An SS -element of X×YX \times Y consists of two component x:SX,y:SYx : S \to X, y : S \to Y and is denoted by (x,y)(x,y) , hence extended the notation of set-theoretic Cartesian product of global elements.