theorem Th63:
  for F being non empty SubStr of D*+^ for p,q being Element of F
  holds p[*]q = p^q
proof
  let F be non empty SubStr of D*+^, p,q be Element of F;
  carr(F) c= carr(D*+^) by Th23;
  then reconsider p9 = p, q9 = q as Element of D*+^;
  thus p[*]q = p9[*]q9 by Th25
    .= p^q by Def34;
end;
