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    Given a category C and a morphism f:X
    ightarrow Y in C, the image of f is a monomorphism h:I
    ightarrow Y satisfying the following universal property:
      There exists a morphism g:X
    ightarrow I such that f = hg.
      For any object Z with a morphism k:X
    ightarrow Z and a monomorphism l:Z
    ightarrow Y such that f = lk, there exists a unique morphism m:I
    ightarrow Z such that k = mg and h = lm.



    The image of f is often denoted by im f or Im(f).

    One can show that a morphism f is monic if and only if f = im f.


        Image (category theory)
            Examples
            See also

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    Examples

    In the category of sets the image of a morphism f
    X o Y is the inclusion from the ordinary image to Y. In many concrete categories such as groups, abelian groups and (left- or right) modules, the image of a morphism is the image of the correspondent morphism in the category of sets.


    In any normal category with a zero object and kernels and cokernels for every morphism, the image of a morphism f can be expressed as follows:

    im f = ker coker f


    This holds especially in abelian categories.

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    See also

     
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    Scientus.org Dictionary (Yet Another Wiki) RC : 1.39
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    This article is licensed under the GNU Free Documentation License [copyleft]. It uses material from the Wikipedia article "Image (category theory)". link