English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In the famous textbook written by Landau and Lifshitz all the vacuum metricsof the general theory of relativity are derived, which depend on one coordinatein the absence of a cosmological constant. Unfortunately, when consideringthese solutions, the authors missed some of the possible solutions discussed inthis article. An exact solution is demonstrated, which is absent in the book byLandau and Lifshitz. It describes space-time with a gravitational wave of zerofrequency. It is shown that there are no other solutions of this type thanlisted above and Minkowski's metrics. The list of vacuum metrics that depend onone coordinate is not complete without the solution provided in this paper.

Vacuum solutions of Einstein equations that depend on one coordinate