reserve X for set,
        n,m,k for Nat,
        K for Field,
        f for n-element real-valued FinSequence,
        M for Matrix of n,m,F_Real;

theorem
  for T be RealLinearSpace,
     Ft be FinSequence of T,
     Fr be FinSequence of RLSp2RVSp(T)
    st Ft = Fr
  holds Sum Ft = Sum Fr;
