reserve a,b,c,d,e,f for Real,
        k,m for Nat,
        D for non empty set,
        V for non trivial RealLinearSpace,
        u,v,w for Element of V,
        p,q,r for Element of ProjectiveSpace(V);

theorem
  <* <* a *>, <* b *>, <* c *> *> is Matrix of 3,1,F_Real
  proof
    rng <* a *> c= REAL;
    then reconsider p = <* a *> as FinSequence of REAL by FINSEQ_1:def 4;
    rng <* b *> c= REAL;
    then reconsider q = <* b *> as FinSequence of REAL by FINSEQ_1:def 4;
    rng <* c *> c= REAL;
    then reconsider r = <* c *> as FinSequence of REAL by FINSEQ_1:def 4;
    len p = 1 & len q = 1 & len r = 1 by FINSEQ_1:40;
    hence thesis by MATRIXR2:34;
  end;
