Exercise 19.16 Let us say that an FD X → Y is simple if Y is a single attribute. Replace t...

Exercise 19.16 Let us say that an FD X → Y is simple if Y is a single attribute.

1. Replace the FD AB → CD by the smallest equivalent collection of simple FDs.
2. Prove that every FD X → Y in a set of FDs F can be replaced by a set of simple FDs such that F⁺ is equal to the closure of the new set of FDs.