Theorem proving is one of the oldest applications which require heuristics to prune the search space. Invertible proof procedures has been the major tool. In this paper, we present a novel and powerful heuristic called $nongshim$ which can be seen as an underlying principle of invertible proof procedures. Using this heuristic, we derive an invertible sequent calculus\cite{Ketonen,Troe} from sequent calculus for propositional logic.

翻译：理论证明是最古老的应用程序之一, 需要超自然学来填补搜索空间。 不可逆的证明程序一直是主要工具。 在本文中, 我们展示了一种新颖而强大的超自然学, 叫做 $nongshim$, 这可以被视为不可逆证据程序的基本原则。 使用这种超自然学, 我们从序列计算中得出了一个不可逆的序列计算法{Ketonen,Troe}, 用于推理逻辑的序列计算法 。