 reserve Rseq, Rseq1, Rseq2 for Function of [:NAT,NAT:],REAL;

theorem SH2:
  for X being non empty set, s being sequence of X, n being Nat
    holds Shift(s|(Segm n),1) is FinSequence of X
proof
   let X be non empty set, s be sequence of X, n be Nat;
   rng Shift(s|(Segm n),1) c= X;
   hence thesis by FINSEQ_1:def 4;
end;
