Calculation Rules of GRT

In this chapter, an attempt is made to summarize the “essentials” of General Relativity Theory (GRT) – as far as they are absolutely necessary for initial practical calculations – in a few pages. In doing so, I refer to the highly recommended books by Steven Weinberg [44-46]. Of course, this brief summary cannot replace a theory course on GRT. However, if one reduces the GRT here only to its calculation rules, without aiming for a deeper understanding of the basics and concepts, a whole lot can already be evaluated with it.