Later we show how the system can be extended to include additional logical connectives, such as ∧ {\displaystyle \land } and ∨ {\displaystyle \lor } , without enlarging the class of deducible formulas.
如下面所讨论的那样，可以把系统扩展为包括额外的逻辑连结词比如 ∧ {\displaystyle \land } 和 ∨ {\displaystyle \lor } ，而不扩大可演绎的公式类。