对自然推理系统P_N中假设前提销去规则(Hyp^-)的理解

Understanding of Rule for Hyp^- Elimination in System of Natural Deduction P_N

自然推理系统中假设前提销去规则是指在引入假设前提推导出结论的过程中,运用蕴涵引入规则构造一个蕴涵式,从而销去假设前提。根据充分条件假言命题为真的情况下前后件之间的关系,只要构造的蕴涵式的前后件都为真,或者前后件都为假,或者前件为假且后件为真,那么这个蕴涵式的逻辑值就是真的,这样就可以销去假设前提了。

The rule of supposed premise elimination in the system of natural deduction is for eliminating the supposed premises by structuring a implication expression in the course of introducing the supposed premises to infer the conclusion. According to the relation of the antecedent and consequent of sufficient condition hypothetical proposition, if the antecedent and consequent are both true, or the antecedent and consequent are both untrue, or the antecedent is true and the consequent is untrue, the implication expression must be true, so we can eliminate the supposed premises.