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

		if (current == null)
			return true;

		T currentV = current.element();
		if (comp.compare(currentV, min) > 0 && comp.compare(currentV, max) < 0)
			return isBST(current.getLeft(), min, currentV)
					&& isBST(current.getRight(), currentV, max);
		else
			return false;

		/**
		 * second thought: not space O(1) 1.in-order add all the elements into
		 * an arraylist,O(n) 2.scan through the al to check the order, then know
		 * if is BST,O(n) Actually, not need for a whole al, just track the last
		 * one. In java, we can either use static var or wrapIn class
		 * 
		 * workable, inorder using iterative and set up a last var. to check
		 * will implement later
		 * 
		 */
	}