reserve k,n for Nat,
  x,y,z,y1,y2 for object,X,Y for set,
  f,g for Function;
reserve p,q,r,s,t for XFinSequence;
reserve D for set;

theorem :: FINSEQ_2:10
  len p <= n implies (p|n) = p
proof
  assume len p<=n;
   then Segm len p c= Segm n by NAT_1:39;
  hence thesis by RELAT_1:68;
end;
