@Iarnav-

**{e.name∣employee(e)∧ NOT(∃x)[employee(x) ^ x.supervisorName = e.name ^ x.sex=‘‘female"]}**

**(∃x)[employee(x) ^ x.supervisorName = e.name ^ x.sex=‘‘female"]**

The highlighted text means tumne ek randomly employee table se tuple select kra

aur check kra ki uska supervisor ka naam is same as the tuple 'e'( ie. e.name) jo consider kra h and yeh jo tuple x hai wo female employee ka hona chahiye.

Means, you select an employee jo kisi female employee ka boss hai.

matlab female employee isko report krti h

Now notice that there is a not symbol also in eq 3.

This implies that wo saare employee de do jo kisi bhi female employee k boss na ho

means koi b female employee inhe report nahi karti.

This is good trick in logic to write expression for "none" kind of statements.

Example : Consider x to be domain of all people in world and B(X) be the predicate that x is best in this world.

Now you write "Someone is best in this world" as ∃x(B(X)).

Now, this ∃x becomes false when there is not even a single value of x which satisfies a predicate.

matlab x ko manlo can take domain values as x1,x2,x3

then ∃x(B(X)) = (B(x1) v B(x2) v B(x3) )

koi b x1,x2,x3 k liye agar B(X) true hua toh ∃x(B(X)) true hoga.

agar kisi k liye nahi hua toh ∃x(B(X)) is false.

So when you place not in it,

∼ ∃x(B(X)) = ∀x(∼B(x1) ^ ∼B(x2) ^ ∼B(x3) )

and this becomes "**No one is best in this world**"

I hope kch smajh aya hoga