A canonical cover F c {\displaystyle F_{c}} for F is a set of dependencies such that F logically implies all dependencies in F c {\displaystyle F_{c}}, and F c {\displaystyle F_{c}} logically implies all dependencies in F. The set F c {\displaystyle F_{c}} has two important properties: No functional dependency in F c {\displaystyle F_{c}} contains an extraneous attribute. Wikipedia