Redundant groups
A groups of 1s or 0s whose all members are overlapped by other groups is called redundant group. We don’t consider this group while writing the simplified equations from the Kmap.
In the above Kmap the group which is represented by the oval is a redundant group and hence while writing the equations we ignore it or we don’t make this kind of group and the Kmap representation becomes as given next:
The equation we get is
F= yz’w’ + x’z’w (ignoring the redundant group)
If we consider this group then equation would be F= yz’w’ + x’z’w + x’yz’
And this is a not the simplified expression and hence WRONG.
Kmap without the redundant group is:
