Proposition: A statement that can be judged true or false is called a proposition. -& gt； Indicates that it can be pushed out.

The original proposition is: a-> b

The antithesis is: b-> a.

No proposition: not A- > not b

The negative proposition is: non-b- > non-a

Reciprocal negative proposition: If the condition and conclusion of one of the two propositions are the negation of the conclusion and condition of the other proposition, the two propositions are called reciprocal negative propositions. The negation of a proposition only negates a conclusion.