
theorem Th12:
  for G being WGraph, W being Walk of G holds W is trivial implies
  W.weightSeq() = {}
proof
  let G be WGraph, W be Walk of G;
  assume W is trivial;
  then W.length() = 0 by GLIB_001:def 26;
  then len W.edgeSeq() = 0 by GLIB_001:def 18;
  then len W.weightSeq() = 0 by Def18;
  hence thesis;
end;
