Natural transformation

Natural transformation

card Let $F,G:C\to D$ be two functors. Collection of morphisms ${\nu }_X:F(X)\to G(X)$, where $X$ are objects from category $C$, is called natural transformation between functors $F$ and $G$, if for each morphism $f:X\to Y$ from the $C$ category ${\nu }_Y\circ F(f)=G(f)\circ {\nu }_X$.

Natural equivalence

card Is equal to Natural transformation, where each ${\nu }_X:F(X)\to F(Y)$ is an Isomorphism.