theorem Th38:
  for L being non degenerated non empty doubleLoopStr, z1,z2 being Element of L
  holds LC <%z1,z2,1.L%> = 1.L
  proof
    let L be non degenerated non empty doubleLoopStr;
    let z1,z2 be Element of L;
    len <%z1,z2,1.L%> = 3 by Th26;
    hence thesis by Lm2,Th23;
  end;
