The contravariant powerset functor $P : C^{op} \rightarrow C$ is the canonical example of duality.
[1] Lawvere, Rosebrugh: "Sets for mathematics"
The contravariant powerset functor $P : C^{op} \rightarrow C$ is the canonical example of duality.
[1] Lawvere, Rosebrugh: "Sets for mathematics"