@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (!(obj instanceof Clause))
			return false;
		Clause other = (Clause) obj;
		if (literals == null) {
			if (other.literals != null)
				return false;
		} else if (!literals.equals(other.literals))
			return false;
		return true;
	}