We study the number of edge flips required to transform any triangulation of an n-vertex spiral polygon into any other. We improve the upper bound from $4n-6$ to $3n-9$ flips and show a lower bound of $2n-8$ flips. Instead of using a single canonical triangulation as the intermediate point in the transformation between two triangulations, we use a family of closely-connected triangulations.

中文翻译：

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螺旋状翻转

我们研究了将n顶点螺旋多边形的任何三角剖分转换为任何其他三角形所需的边缘翻转次数。我们提高了上限$4ñ-6$ 至 $3ñ-9$ 翻转并显示下限 $2ñ-8$翻转。我们不使用单个规范化的三角剖分作为两个三角剖分之间转换的中间点，而是使用一系列紧密相连的三角剖分。