In his 1936 paper "Finite Combinatory Processes—Formulation 1" (which can be found on page 289 of Undecidable), Emil Post described a model of extreme simplicity which he conjectured is "logically equivalent to recursiveness", and which was later proved to be so.
在他1936年的论文"Finite combinatory processes—formulation 1"（可以在The Undecidable的289页找到它），Emil Post描述了非常简单的一个模型，它被猜测为"逻辑上等价于递归函数"，并且后来被证明确实如此。