In this case, and is characterized by the following rules: An apparent problem with this was pointed out by Arthur Prior: Why can't we have an expression (call it "tonk") whose introduction rule is that of OR (from "p" to "p tonk q") but whose elimination rule is that of AND (from "p tonk q" to "q")?
在这种情况下，“与”被如下规则所特征化: Arthur Prior 指出了它的一个明显的问题: 为什么不能有一个表达(称它为"tonk")，它的介入规则是 OR 形式的(从 "p" 到 "p tonk q") 而它的除去规则是 AND 形式的(从 "p tonk q" 到 "q")?