Definition:Colimit

Definition
Let $\mathbf C$ be a metacategory.

Let $D: \mathbf J \to \mathbf C$ be a $\mathbf J$-diagram in $\mathbf C$.

Let $\map {\mathbf {Cocone} } D$ be the category of cocones from $D$.

A colimit for $D$ is an initial object in $\map {\mathbf {Cocone} } D$.

It is denoted by $\varinjlim_j D_j$; the associated morphisms $\iota_i: D_i \to \varinjlim_j D_j$ are usually left implicit.

Also known as
The most important other name for this concept is direct limit.

Some authors speak of colimiting cones.

Also see

 * Limit (Category Theory), the dual notion