The theory of gravitational lensing is reviewed from a spacetime perspective, without quasi-Newtonian approximations. More precisely, the review covers all aspects of gravitational lensing where light propagation is described in terms of lightlike geodesics of a metric of Lorentzian signature. It includes the basic equations and the relevant techniques for calculating the position, the shape, and the brightness of images in an arbitrary general-relativistic spacetime. It also includes general theorems on the classification of caustics, on criteria for multiple imaging, and on the possible number of images. The general results are illustrated with examples of spacetimes where the lensing features can be explicitly calculated, including the Schwarzschild spacetime, the Kerr spacetime, the spacetime of a straight string, plane gravitational waves, and others.

中文翻译：

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从时空角度看引力透镜。


从时空角度回顾引力透镜理论，没有准牛顿近似。更准确地说，该评论涵盖了引力透镜的所有方面，其中光传播是用洛伦兹签名度量的类光测地线来描述的。它包括计算任意广义相对论时空中图像的位置、形状和亮度的基本方程和相关技术。它还包括关于焦散分类、多重成像标准以及可能的图像数量的一般定理。一般结果以可以明确计算透镜特征的时空为例进行说明，包括史瓦西时空、克尔时空、直弦时空、平面引力波等。