reserve G for Go-board,
  i,j,k,m,n for Nat;

theorem Th10:
  for f,g being FinSequence holds rng f c= rng(f^'g)
proof
  let f,g be FinSequence;
  f^'g = f^(2, len g)-cut g by FINSEQ_6:def 5;
  hence thesis by FINSEQ_1:29;
end;
