Geometric theories based on classical logic are conservative over their intuitionistic counterparts for geometric implications. The latter result (sometimes referred to as Barr's theorem) is squarely a consequence of Gentzen's Hauptsatz. Prima facie though, cut elimination can result in superexponentially longer proofs. In this paper it is shown that the transformation of a classical proof of a geometric implication in a geometric theory into an intuitionistic proof can be achieved in feasibly many steps.
翻译:基于古典逻辑的几何理论与其对几何影响的直觉对应理论相比是保守的。 后一种结果(有时被称为Barr的理论)完全来自于Gentzen的Hauptsatz。 初步看来,削减可能会导致超速更长的证据。 本文表明,将几何理论中几何含义的古典证据转化为直觉证据可以通过可行的许多步骤实现。