public void testMultipleClauseResolution()
{
// test (and fix) suggested by Huy Dinh. Thanks Huy!
PLResolution plr = new PLResolution();
KnowledgeBase kb = new KnowledgeBase();
String fact = "((B11 <=> (P12 OR P21)) AND (NOT B11))";
kb.tell(fact);
plr.plResolution(kb, "(B)");
}