Steps to Find Minimal Cover
1) Split the right-hand attributes of all FDs.
Example
A->XY => A->X, A->Y
2) Remove all redundant FDs.
Example
{ A->B, B->C, A->C }
Here A->C is redundant since it can already be achieved using the Transitivity Property.
3) Find the Extraneous attribute and remove it.
Example
AB->C, either A or B or none can be extraneous.
If A closure contains B then B is extraneous and it can be removed.
If B closure contains A then A is extraneous and it can be removed.
Example 1
Minimize {A->C, AC->D, E->H, E->AD}
Step 1: {A->C, AC->D, E->H, E->A, E->D}
Step 2: {A->C, AC->D, E->H, E->A}
Here Redundant FD : {E->D}
Step 3: {AC->D}
{A}+ = {A,C}
Therefore C is extraneous and is removed.
{A->D}
Minimal Cover = {A->C, A->D, E->H, E->A}
