theorem BLTh30:
  for V, W being right_zeroed non empty ModuleStr over INT.Ring,
  f being additiveSAF Form of V,W,
  w being Vector of W holds f.(0.V,w) = 0
  proof
    let V, W be right_zeroed non empty ModuleStr over INT.Ring;
    let f be additiveSAF Form of V,W, v be Vector of W;
    f.(0.V,v) = f.(0.V+0.V,v) by RLVECT_1:def 4
    .= f.(0.V,v) + f.(0.V,v) by BLTh26;
    hence thesis;
  end;
