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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

When, at the end of the year 1915, both Einstein and Hilbert arrived at whatwere named the field equations of general relativity, both of them thought thattheir fundamental achievement entailed, inter alia, the realisation of a theoryof gravitation whose underlying group was the group of general coordinatetransformations. This group theoretical property was believed by Einstein to bea relevant one from a physical standpoint, because the general coordinatesallowed to introduce reference frames not limited to the inertial referenceframes that can be associated with the Minkowski coordinate systems, whosetransformation group was perceived to be restricted to the Poincar\'e group.Two years later, however, Kretschmann published a paper in which the physicalrelevance of the group theoretical achievement in the general relativity of1915 was denied. For Kretschmann, since any theory, whatever its physicalcontent, can be rewritten in a generally covariant form, the group of generalcoordinate transformations is physically irrelevant. This is not the case,however, for the group of the infinitesimal motions that bring the metric fieldin itself, namely, for the Killing group. This group is physicallycharacteristic of any given spacetime theory, since it accounts for the localinvariance properties of the considered manifold, i.e., for its ``relativitypostulate''. In the present chapter it is shown what are the consequences forthe physical interpretation of some of these solutions whose relativitypostulate is of intermediate content, when Kretschmann's standpoint isconsistently adhered to.

The group aspect in the physical interpretation of general relativity theory