reserve Q,Q1,Q2 for multLoop;
reserve x,y,z,w,u,v for Element of Q;

theorem Th2:
  y * x = u & z * x = u implies y = z
proof
  assume y * x = u & z * x = u;
  then (y * x) / x = (z * x) / x;
  hence thesis;
end;
