theorem Th37:
  b "**" <%d%> = d
proof
  len<%d%> = 1 by AFINSQ_1:33;
  then ex f be sequence of D st f.0=<%d%>.0& (for n st n+1 < len <%d%>
  holds f.(n+1) = b.(f.n,<%d%>.(n+1)))& b "**" <%d%>=f.(1-1) by Def8;
  hence thesis;
end;
