clarified transitive_closure: proper cumulation of transitive steps, which is essential for Warshall-style algorithms;
clarified transitive_closure: proper cumulation of transitive steps, which is essential for Warshall-style algorithms;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle