In modern philosophy, mathematics, logic and linguistics, proposition (judgment) refers to the semantics of a judgment sentence (the concept of actual expression), which can be defined and observed.

Proposition refers not to the judgment sentence itself, but to the semantics expressed. When different sentences have the same semantics, they express the same proposition. In mathematics, a declarative sentence to judge something is generally called a proposition.

Proposition form:

1. For two propositions, if the conditions and conclusions of one proposition are the conclusions and conditions of the other, then these two propositions are called reciprocal propositions, one of which is called the original proposition and the other is called the inverse proposition of the original proposition.

2. For two propositions, if the conditions and conclusions of one proposition are the negation of the conditions and conclusions of the other, then these two propositions are called mutually negative propositions, one of which is called the original proposition and the other is called the negative proposition of the original proposition.

3. For two propositions, if the condition and conclusion of one proposition are the negation of the conclusion and condition of the other proposition, then these two propositions are called mutually negative propositions, one of which is called the original proposition and the other is called the negative proposition of the original proposition.