Definition:Composable Morphisms

Definition
Let $\mathbf C$ be a metacategory.

Let $f, g \in \mathbf C_1$ be morphisms of $\mathbf C$.

Then $f$ is said to be composable with $g$ iff:


 * $\operatorname{cod} f = \operatorname{dom} g$

that is, iff the codomain of $f$ is the domain of $g$.

When the order of composition is to be made more explicit, one says that $\left({g, f}\right)$ is a composable pair.

The collection of all such composable pairs in $\mathbf C$ is denoted $\mathbf C_2$.

Also see

 * Morphism
 * Metacategory