Negation (NOT)
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🚫 Negation (NOT)
In logic, Negation means saying the opposite of something.
It is written as:
👉 ~p
(or sometimes just ¬p)
Read as: “NOT p”
🧠 What does it mean?
Negation changes the truth value of a statement:
-
If something is True (1) → NOT makes it False (0)
-
If something is False (0) → NOT makes it True (1)
🔄 Real-Life Example:
Let’s say:
-
p = "It is raining."
Then:
-
~p = "It is NOT raining."
So, if p is True (yes, it is raining), then ~p is False (no, it's not raining — which would be a lie).
🔢 Truth Table for ~p (Using 0 and 1)
| p | ~p |
|---|---|
| 0 | 1 |
| 1 | 0 |
📌 Summary:
| Statement p | NOT p (~p) | Meaning |
|---|---|---|
| 0 (False) | 1 (True) | If the statement is false, then "not" makes it true |
| 1 (True) | 0 (False) | If the statement is true, then "not" makes it false |
🎉 Tip:
Negation is like flipping a switch:
-
ON becomes OFF
-
YES becomes NO
-
TRUE becomes FALSE