theorem Th152:
  for R being non empty addLoopStr, a being Element of R,
  i be Integer st i=0 holds
  (Int-mult-left(R)).(i,a) = 0.R
  proof
    let R be non empty addLoopStr,
    a be Element of R, i be Integer;
    assume i=0;
    hence (Int-mult-left(R)).(i,a) = 0 * a by Def23
    .=0.R by BINOM:12;
  end;
