
theorem Th7:
  for p, q being FinSequence for j being Nat st j <= len maxPrefix(
  p,q) holds p.j = q.j
proof
  let p, q be FinSequence;
  let j be Nat such that
A1: j <= len maxPrefix(p,q);
  thus p.j = maxPrefix(p,q).j by A1,Th6
    .= q.j by A1,Th6;
end;
