nLab unnatural transformation

Definition

Given categories $C,D$ and functors $F,G\colon C \to D$, an unnatural transformation from $F$ to $G$ consists of, for each object $x$ of $C$, a morphism from $F(x)$ to $G(x)$ in $D$.

Thus a natural transformation is an unnatural transformation that satisfies an extra property, namely naturality.

Related pages

• unnatural isomorphism
• funny tensor product