We present a streamlined and simplified exponential lower bound on the length of proofs in intuitionistic implicational logic, adapted to Gordeev and Haeusler's dag-like natural deduction.

翻译：我们针对Gordeev和Haeusler的类有向无环图自然演绎系统，提出了一种经过简化的指数级证明长度下界。