 
Summary: arXiv:grqc/0412102
v2
11
Aug
2005
THE PHYSICAL MEANING OF THE \BOOSTROTATION
SYMMETRIC" SOLUTIONS WITHIN THE GENERAL
INTERPRETATION OF EINSTEIN'S THEORY OF
GRAVITATION
SALVATORE ANTOCI, DIERCKEKKEHARD LIEBSCHER, AND LUIGI MIHICH
Abstract. The answer to the question, what physical meaning should
be attributed to the socalled boostrotation symmetric exact solutions
to the eld equations of general relativity, is provided within the general
interpretation scheme for the \theories of relativity", based on group
theoretical arguments, and set forth by Erich Kretschmann already in
the year 1917.
1. Introduction
In the same year 1915, when Einstein and Hilbert [1, 2] gave the nal
mathematical expression to the long eorts done by Einstein for nding a
generally covariant theory of gravitation based on the absolute dierential
