public boolean isBST2(BTPosition<T> current, T min) {

		if (current == null)
			return true;
		Stack<BTPosition<T>> s = new Stack<>();

		while (!s.isEmpty() || current != null) {
			if (current != null) {
				s.push(current);
				current = current.getLeft();
			} else {
				current = s.pop();
				if (comp.compare(min, current.element()) > 0)
					return false;
				min = current.element();
				current = current.getRight();
			}
		}
		return true;

	}