A general formalism recently proposed to study Newtonian polytropes for anisotropic fluids (Abellán et al., 2020) is here extended to the relativistic regime. Thus, it is assumed that a polytropic equation of state is satisfied by, both, the radial and the trangential pressures of the fluid. Doing so the generalized Lane–Emden equations are obtained and solved. Some specific models are obtained, and their physical properties are discussed.

中文翻译：

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各向异性的广义相对论双多向性

最近提出的一种一般形式主义，用于研究各向异性流体的牛顿多向性（Abellán等，2020），在这里扩展到相对论体系。因此，假定流体的径向压力和切向压力都满足多态状态方程。这样就获得并求解了通用的Lane-Emden方程。获得了一些特定的模型，并讨论了它们的物理性质。