Given a set of $n$ labeled points in general position in the plane, we remove all of its points one by one. At each step, one point from the convex hull of the remaining set is erased. In how many ways can the process be carried out? The answer obviously depends on the point set. If the points are in convex position, there are exactly $n!$ ways, which is the maximum number of ways for $n$ points. But what is the minimum number? It is shown that this number is (roughly) at least $3^n$ and at most $12.29^n$.
翻译:给定一个平面上的 $n$ 个标记点,在一开始,我们移除所有点。在每一步中,从剩余点的凸包中擦除一个点。这个过程可以以多少种方式进行?答案显然取决于点集。如果点位于凸位置,则有正好 $n!$ 种方式,这是 $n$ 点的最大数量。但是最小的数量是多少?它被证明大约为 $3^n$ 到 $12.29^n$ 之间。