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What do the symbols "E is upside down" and "A is upside down" in the mathematical simple logic and set mean?
"E-turn in turn" is the symbol of "existence" in mathematics. , used for special propositions.

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 .