source plogdiff subst_test source plogdiff equal_sub_test source plogdiff equal_equiv_test source plogdiff simple_q_test source plogdiff free_test source plogdiff mismatch_test source plogdiff subproof_q_test source plogdiff kaye_ch9_test source plogdiff hr_ch2_test source plogdiff back_test source plogdiff backa_test source plogdiff count_test source plogdiff type_test source plogdiff fol_apply_test # source plogdiff fol_save_test