When functional dependency F is said to be minimal?

When functional dependency F is said to be minimal?

F to be minimal if it satisfies the following conditions:

1. Every dependency in F has a single attribute for its right hand side. 
2. We cannot replace any dependency X → A in F with dependency Y → A, where Y is a proper subset of X, and still have a set of dependencies that is equivalent to F.
3. We cannot remove any dependency from F and still have a set of dependencies that is equivalent to F.