reserve i,j,k,n,m for Nat,
  x,y,z,y1,y2 for object, X,Y,D for set,
  p,q for XFinSequence;
reserve k1,k2 for Nat;
reserve D for non empty set,
  F,G for XFinSequence of D,
  b for BinOp of D,
  d,d1,d2 for Element of D;

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;
