We investigate the relation between quadrics and their Christoffel duals on the one hand, and certain zero mean curvature surfaces and their Gauss maps on the other hand. To study the relation between timelike minimal surfaces and the Christoffel duals of 1-sheeted hyperboloids we introduce para-holomorphic elliptic functions. The curves of type change for real isothermic surfaces of mixed causal type turn out to be aligned with the real curvature line net.

中文翻译：

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二次曲线和 Scherk 塔

我们一方面研究二次曲面与其 Christoffel 对偶之间的关系，另一方面研究某些零平均曲率曲面及其高斯图之间的关系。为了研究类时最小曲面与 1 片双曲面的 Christoffel 对偶之间的关系，我们引入了准全纯椭圆函数。混合因果类型的真实等温面的类型变化曲线与真实曲率线网对齐。