然后，再将非退化二阶曲线到自身的双射为对合的充要条件推广到退化二阶曲线两相异点列的情形。

Then, the latter necessary and sufficient condition is generalized to the case for the two different point ranges of degenerate second order curve.

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我们已经研究了分别具椭圆和双曲不动点的二维保测度映射及其受摄三维扩张的KS熵。

We have studied the KS entropy of a 2-dimensional measure-preserving mapping with an elliptic or hyperbolic fixed point respectively, as well as that of its 3-dimensional extension.

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通过测量拱腹各点坐标来确定双曲拱桥每孔的拱轴线。

According to measuring the coordinates of each span of long span double arched bridge, the arch axis for every span is determined.

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