Under study are the graph mappings constructed from the contact mappings of arbitrary Carnot groups. We establish the well-posedness conditions for the problem of maximal surfaces, introduce a suitable notion of the increment of the (sub-Lorentzian) area functional, and prove that this functional is differentiable. The necessary maximality conditions for graph surfaces are described in terms of the area functional as well as in terms of sub-Lorentzian mean curvature.

中文翻译：

---

卡诺组上的最大曲面的类别

研究中的图映射是由任意卡诺组的接触映射构成的。我们建立了最大曲面问题的适定性条件，引入了（次洛伦兹）面积函数增量的适当概念，并证明了该函数是可微的。根据面积函数以及亚洛伦兹平均曲率来描述图形表面的必要最大条件。