The Catalan numbers also count the number of ways in which ann-gon can be dissected into triangles by nonintersecting diagonals.

加泰隆数又是用不相交的对角线划分几边形成三角形的方式数。

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Let P and Q be two nonintersecting simple polygons in the plane, this paper discusses the rotational movability of them if P rotates around a point and collides with Q .

设P和Q为平面内两个互不相交的简单多边形 ，若 P在平面内绕某点旋转 ，文中讨论了其旋转可移动性问题 。

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Let P and Q be two nonintersecting simple polygons in the plane, this paper discusses the rotational movability of them if P rotates around a point and collides with Q .

设P和Q为平面内两个互不相交的简单多边形 ，若 P在平面内绕某点旋转 ，文中讨论了其旋转可移动性问题 。

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