We study the remainder of chapter 7 upto and including section 7.3.3.
The sections 7.3.2 and 7.3.3 deal with the topic of “closure”.
In section 7.3.2 the closure of a set of functional dependencies is discussed, using inference rules. An important aspect is that when you define a new inference rule you want to verify whether it really adds something to the set of rules you already have. Proving rules by using other rules is something we are going to practice a lot.
In section 7.3.3 the closure of a set of attributes is discussed. These are all the attributes that are functionally dependent on a given set of attributes. Here too the concept of inference rules plays an important role.