Existential quantifier? X: P(x) means that at least one x makes P(x) true. ? N ∈ N: n is even.

Existential quantifiers, such as some, at least one, one, existence and other phrases. There are words that express individual or partial meanings. Propositions containing existential quantifiers are called special propositions. Its form is several s and p. Special propositions use existential quantifiers, such as some and several. You can also use basic, general, just some, etc.

Extended data:

Words such as "to the full amount" and "to any amount" are logically called full-name quantifiers and recorded as "?" A proposition that contains a full-name quantifier is called a universal proposition.

For any x in m, there is p(x), which is recorded as? x∈M，p(x)

Read: for any x belonging to m, p(x) holds.

Full name proposition: its formula is "all S with total quantity are P"

Full-name propositions can be expressed by full-name quantifiers, or by the repetition of subjects such as "everyone", or even without any quantifier symbols, such as "all mankind is wise."

Because algebraic theorems use full-name quantifiers, each algebraic theorem is a full-name proposition. It is also the full-name quantifier that makes the identity transformation by bringing in rules become the core of algebraic reasoning.

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