Polycarbonate Diols (PCD) are used for a wide range of polyurethane-based coating formulations, providing an extreme durability and a high performance to the final polymer. ok
In mathematics, a reciprocity law is a generalization of the law of quadratic reciprocity. There are several different ways to express reciprocity laws.
Admittedly, that's looking at the Law of Reciprocity from a much deeper perspective that transcends the physical, but so do each of the events, conditions and circumstances both given and received which The Law of Reciprocity determines.