theorem Th5:
  e in the carrier' of G implies <*e*> is Simple oriented Chain of G
proof
  assume e in the carrier' of G;
  then
A1: <*e*> is FinSequence of the carrier' of G by FINSEQ_1:74;
  len <*e*> = 1 by FINSEQ_1:40;
  hence thesis by A1,GRAPH_5:15;
end;
