前言
原文：Prolog powerset predicate [closed]

我想界定一个在P是X权力时即属实的上游权力。 如果工作是不是P 。

编制所有可能的图表,以保存vert号
原文：Generate all possible subgraphs of a directed graph keeping the number of vertices

I have two lists of vertices: V and S. I would like to generate all possible directed graphs from V and S so, that each vertex from V has only one out-edge and exactly one in-edge, and each vertex ...