Comparing Functional Dependencies
Entailment: a set of functional dependencies S1 entails a set S2 if:
any database that satisfies S1 much also satisfy S2.
Example: A B, B C entails A C
Equivalence: two sets of FD’s are equivalent if each entails the other.
{A B, B C } is equivalent to {A B, A C, B C}
Closure: Given a set of attributes A and a set of dependencies C,
we want to find all the other attributes that are functionally