For example:? X∈R, x>4, this proposition means that the existence of X belongs to the set of real numbers, which makes the inequality X >；; 4 established.

"One inversion" is the symbol of "arbitrariness" in mathematics. Used for full name proposition.

For example:? X∈, x>4, this proposition means: any X belongs to a real number set and there is an inequality X >；; 4 established.

The negation of special propositions can be expressed by complete propositions, and vice versa. Just release it? Become? Just deny the second half.

For example:? What is the negative number of x∈R and x>4? x∈，x≤4 .