added graph operations for transitive closure and reduction in Scala -- unproven and thus better left out of the kernel-relevant ML module;
added graph operations for transitive closure and reduction in Scala -- unproven and thus better left out of the kernel-relevant ML module;

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