code: public RangeBigInteger intersect(RangeBigInteger r) {
  		if (min.compareTo(r.max) > 0) return null;
  		if (max.compareTo(r.min) < 0) return null;
  		return new RangeBigInteger(min.compareTo(r.min) <= 0 ? r.min : min, max.compareTo(r.max) <= 0 ? max : r.max);
  	}
docs: Return the intersection between this range and the given range.