if the goal contains no constants or frees, fall back on chained facts, then on local facts, etc., instead of generating a trivial ATP problem
(* Title: HOL/SET_Protocol/ROOT.ML
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 2003 University of Cambridge
Root file for the SET protocol proofs.
*)
no_document use_thys ["Nat_Bijection"];
use_thys ["Cardholder_Registration", "Merchant_Registration", "Purchase"];