I. Denial
Negation is a logical operation to change the true value or false value of a proposition. If a proposition is true, then its negation is false; On the other hand, the negation of any proposition P from Dallas to the auditorium is not P.
In propositional logic, negation usually uses the symbol "?" Express delivery. For example, what is the negation of the proposition "P"? p .
Second, there is no proposition.
No proposition is a logical operation that changes the conditions and conclusions of a proposition. If the conditions and conclusions of a proposition are true, then its negative proposition is false; If its conditions and conclusions are false, then its negative proposition is true.
In propositional logic, negative propositions are usually represented by the symbol "￢". "For example, the negative proposition of the proposition" If P, then Q "is" If? What about p? Ask.
Third, the difference between negative proposition and negative proposition.
Negation mainly focuses on the true and false values of propositions, and negates the conditions and conclusions of propositions. Negation is a logical operation based on the existing proposition, and negative proposition is a new proposition based on the conditions and conclusions of the original proposition.
The Application of Negative Proposition in Logic and Daily Life
1, the application in logic
In logic, the conditions and conclusions of a negative proposition are reversed at the same time. If the original proposition is true, its negative proposition may be false; Or vice versa, taking Dallas to the auditorium as an example, we have a proposition: "If a person is single, then he/she has no spouse." The negative proposition of this proposition is: "If a person has a spouse, then he/she is not single."
Step 2 use it in daily life
In daily life, the use of negation and negative propositions is also very common. For example, we often hear such words: "I don't think he will come." "No" here is a negative word. Or we can say, "Not all cats like fish." "No" here is also a negative word.