论文部分内容阅读
一、数学命题的四种形式及其关系Ⅰ.若A则B。(原命题) Ⅱ.若B则A。(逆命题) Ⅲ.若。(否命题) Ⅳ。(逆否命题) 四种命题的关系如右图所示。可以证明,命题Ⅰ与Ⅳ是等价的。证明:先证“若A则B
First, the four forms of mathematical propositions and their relationships I. If A then B. (Original proposition) II. If B is A. (Contradictions) III. (No proposition) IV. (Contradictory No Proposition) The relationship between the four propositions is shown in the right figure. It can be shown that Proposition I and IV are equivalent. Proof: First Testimony "If A then B