Italian symbol (full name quantifier)? Derived from the English word Arbitrary, because lowercase and uppercase are easily confused, the first letter of the word is capitalized and then inverted. Similarly, existential number (existential quantifier)? Reverse writing of e from the word Exist.

Full-name quantifier: the phrases "to all" and "to any" indicate all or all the meanings in the statement. Logically, it is usually called a full-name quantifier, which is represented by the symbol "".

Existential quantifier: The phrases "You Yi" and "At least one" indicate the meaning of an individual or part in a statement, and are usually called existential quantifiers in logic, and are represented by the symbol "".

Extended data:

1, full-name quantifier and full-name proposition:

Full-name proposition: A proposition containing full-name quantifiers is called a full-name proposition.

The format of full-name proposition: the proposition that "for any X in M, p(x) holds" is recorded as x∈M, p(x), which is read as "for any X, it belongs to M, and p(x) holds".

2. There are quantifiers and special propositions;

Special proposition: A proposition containing existential quantifiers is called a special proposition.

There is a x0 in M, which makes p(x0) hold. X0∈M, p(X0), pronounced as "there is an x0 belonging to m, so p(x0) holds".

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