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);
reserve o,p,q,r,s,t for Point of TOP-REAL 3,
        M for Matrix of 3,F_Real;
reserve pf for FinSequence of D;
reserve PQR for Matrix of 3,F_Real;

theorem
  len pf = 3 implies
  <* Col(<*pf*>,1), Col(<*pf*>,2), Col(<*pf*>,3) *> = F2M pf
  proof
    assume
A0: len pf = 3;
    then Col(<*pf*>,1) = <* pf.1 *> & Col(<*pf*>,2) = <* pf.2 *> &
    Col(<*pf*>,3) = <* pf.3 *> by Th51;
    hence thesis by A0,DEF1;
   end;
