 reserve R for Ring;
 reserve x, y, y1 for set;
 reserve a, b for Element of R;
 reserve V for LeftMod of R;
 reserve v, w for Vector of V;
 reserve u,v,w for Vector of V;
 reserve F,G,H,I for FinSequence of V;
 reserve j,k,n for Nat;
 reserve f,f9,g for sequence of V;
 reserve R for Ring;
 reserve V, X, Y for LeftMod of R;
 reserve u, u1, u2, v, v1, v2 for Vector of V;
 reserve a for Element of R;
 reserve V1, V2, V3 for Subset of V;
 reserve x for set;
 reserve W, W1, W2 for Submodule of V;
 reserve w, w1, w2 for Vector of W;
 reserve D for non empty set;
 reserve d1 for Element of D;
 reserve A for BinOp of D;
 reserve M for Function of [:the carrier of R,D:],D;
reserve B,C for Coset of W;
 reserve V for LeftMod of R;
 reserve W, W1, W2, W3 for Submodule of V;
 reserve u, u1, u2, v, v1, v2 for Vector of V;
 reserve a, a1, a2 for Element of R;
 reserve X, Y, y, y1, y2 for set;
 reserve C for Coset of W;
 reserve C1 for Coset of W1;
 reserve C2 for Coset of W2;
reserve A1,A2,B for Element of Submodules(V);

theorem Th163:
  for R being Abelian right_zeroed add-associative right_complementable
    non empty addLoopStr,
  a being Element of R, i, j being Element of INT.Ring holds
  (Int-mult-left(R)).(i*j,a) = (Int-mult-left(R)).(i,(Int-mult-left(R)).(j,a))
  proof
    let R be Abelian right_zeroed add-associative right_complementable
    non empty addLoopStr,
    a be Element of R, i, j be Element of INT.Ring;
    per cases;
    suppose i = 0 or j = 0;
      hence (Int-mult-left(R)).(i*j,a)
      =(Int-mult-left(R)).(i,(Int-mult-left(R)).(j,a)) by Lm20;
    end;
    suppose not (i = 0 or j = 0);
      hence (Int-mult-left(R)).(i*j,a)
      =(Int-mult-left(R)).(i,(Int-mult-left(R)).(j,a)) by Lm19;
    end;
  end;
