added check_result;
setmp Display.show_hyps false;
fixed auto_bind_facts;
tuned finish_proof;
fixed backtracking of global_qed;
consts sep :: "'a * 'a list => 'a list"
recdef sep "measure (%(a,xs). length xs)"
"sep(a, []) = []"
"sep(a, [x]) = [x]"
"sep(a, x#y#zs) = x # a # sep(a,y#zs)"