
theorem Th3:
  for L be non empty ZeroStr holds len 0_.(L) = 0
proof
  let L be non empty ZeroStr;
  for i being Nat holds i >= 0 implies (0_.(L)).i = 0.L
    by FUNCOP_1:7,ORDINAL1:def 12;
  then 0 is_at_least_length_of 0_.(L);
  hence thesis by ALGSEQ_1:def 3;
end;
