二次曲面的投影束与Ivory定理
Projection pencil of quadrics and Ivory theorem
摘要：
我们改写了伪欧几里得空间上的共焦性质。我们的观察是，$\cite{stachel}$中的共焦性的广义定义并没有回到欧几里得二次曲线的共焦性的原始定义。当投影变换是正则的，即空间的恒等变换时，$\cite{stachel}$的“共焦性”可以从我们的定义中得到。我们的检查集中在奇异的情况下，太，因为他们发挥重要作用的调查基本的例子。
英文摘要：
We rewrite the property of confocality with respect to a pseudo-Euclidean space. Our observation is that the generalized definition of confocality in $\cite{stachel}$ does not give back to the original definition of confocality of Euclidean conics. The "confocality property" of $\cite{stachel}$ can be get from our definition in the case when the projection transformation is regular, it is the identity transformation of the space. Our examination concentrate to the singular cases, too because they are playing important role in the investigations of essential examples.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
