private Rule removeDefeater_transformDefeater(Rule origRule) throws TheoryNormalizerException {
		if (origRule.getRuleType() != RuleType.DEFEATER) return null;

		List<Literal> origHeadLiterals = origRule.getHeadLiterals();

		if (origHeadLiterals.size() > 1) throw new TheoryNormalizerException(getClass(),
				"rule head contains more than 1 literal");
		Literal origHeadLiteral = origHeadLiterals.get(0);
		Mode dummyLiteralMode = origHeadLiteral.getMode();
		Mode ruleMode = origRule.getMode();
		if ("".equals(dummyLiteralMode.getName())) dummyLiteralMode = ruleMode;
		String sign = (origHeadLiteral.isNegation()) ? "+" : "-";

		Rule newRule = DomUtilities.getRule(origRule.getLabel(), RuleType.DEFEASIBLE);
newRule.setOriginalLabel(origRule.getOriginalLabel());
		newRule.setMode(ruleMode);
		try {
			addBodyLiterals(newRule, origRule.getBodyLiterals(), "");
			newRule.addHeadLiteral(DomUtilities.getLiteral(origHeadLiteral.getName() + sign, true, dummyLiteralMode,null,
					(String[]) null, true));
		} catch (Exception e) {
		}

		return newRule;
	}