theorem
  for G being non empty DTConstrStr for s being Element of G
  for p being FinSequence st s ==> p
  holds p is FinSequence of the carrier of G
proof
  let G be non empty DTConstrStr;
  let s be Element of G;
  let p be FinSequence;
  assume s ==> p;
  then [s,p] in the Rules of G;
  then p in (the carrier of G)* by ZFMISC_1:87;
  hence thesis by FINSEQ_1:def 11;
end;
