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===Colimits=== {{see also|Direct limit}} The [[Dual (category theory)|dual notions]] of limits and cones are colimits and co-cones. Although it is straightforward to obtain the definitions of these by inverting all morphisms in the above definitions, we will explicitly state them here: A '''[[co-cone]]''' of a diagram <math>F:J\to C</math> is an object <math>N</math> of <math>C</math> together with a family of morphisms :<math>\psi_X:F(X) \to N</math> for every object <math>X</math> of <math>J</math>, such that for every morphism <math>f:X\to Y</math> in <math>J</math>, we have <math>\psi_Y\circ F(f)=\psi_X</math>. A '''colimit''' of a diagram <math>F:J\to C</math> is a co-cone <math>(L, \phi)</math> of <math>F</math> such that for any other co-cone <math>(N, \psi)</math> of <math>F</math> there exists a unique morphism <math>u:L\to N</math> such that <math>u\circ \phi_X = \psi_X</math> for all <math>X</math> in <math>J</math>. [[File:Functor co-cone (extended).svg|center|A universal co-cone]] Colimits are also referred to as ''[[universal co-cone]]s''. They can be characterized as [[initial object]]s in the [[category of co-cones]] from <math>F</math>. As with limits, if a diagram <math>F</math> has a colimit then this colimit is unique up to a unique isomorphism.
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