}
} else if (hClause instanceof Rule) {
Rule r = (Rule)hClause;
if (r.isBackward()) {
if (isAdd) {
infGraph.addBRule(r.instantiate(env));
} else {
infGraph.deleteBRule(r.instantiate(env));
}
} else {
throw new ReasonerException("Found non-backward subrule : " + r);