reserve n for Nat;

theorem Th2:
  for D be non empty set for f be FinSequence of D for G be Matrix
  of D for p be set holds f is_sequence_on G implies f-:p is_sequence_on G
proof
  let D be non empty set;
  let f be FinSequence of D;
  let G be Matrix of D;
  let p be set;
  assume f is_sequence_on G;
  then f|(p..f) is_sequence_on G by GOBOARD1:22;
  hence thesis by FINSEQ_5:def 1;
end;
