  A folklore result in category theory is that a (weakly) Cartesian closed
category with finite co-products is distributive. Usually, the proof of this
small result is carried on using the fact that the exponential functor is right
adjoint to the product functor. And, since functors having a right adjoint
preserve co-limits, the result follows immediately. But, when we try to
explicitly construct the arrows, things become a bit more involved. In rare
cases, it is pretty useful to have the exact arrows that make this isomorphism
to hold. The purpose of this note is to develop the explicit proof with all the
involved arrows constructed in an explicit way.
