In mathematics, declarative sentences that judge things are generally called propositions, and propositions refer to the semantics (concepts actually expressed) of judging (statements).

Definition originally refers to a clear description of the value of things. It is equivalent to the assignment of unknowns in mathematics. For example, "Let an unknown be a known letter X to simplify the calculation", and give a certain meaning or image to the named words, which is beneficial to the identification and recognition in communication.

2. Function

Proposition: a statement used to judge a thing; A statement that can judge whether it is true or false; Generally speaking, in mathematics, we call declarative sentences that can judge the truth of propositions expressed by language, symbols or formulas as declarative sentences; Among them, statements judged to be true are called true propositions, and statements judged to be false are called false propositions.

Definition: used to accurately express the essential characteristics of a thing or the connotation and extension of a concept. The most representative definition is the definition of "species difference+genus", that is, to include a concept in its genus concept and reveal its differences with other concepts under the same genus concept.

Extended data:

Classification of propositions:

1, original proposition: A proposition itself is called the original proposition. For example, if x> 1, then f (x) = (x- 1) 2 monotonically increases.

2. Inverse proposition: a new proposition with the opposite conditions and conclusions to the original proposition. For example, if f (x) = (x- 1) 2 monotonically increases, then x> 1.

3. No proposition: a new proposition that completely negates the conditions and conclusions of the original proposition, but does not change the order of conditions and conclusions, such as: if X.

4. Negative proposition: a new proposition that reverses the conditions and conclusions of the original proposition, and then completely negates these conditions and conclusions, such as: if f (x) = (x- 1) 2 is not monotonically increasing, then x < = 1.

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