Lorentz semigroup
Abstract
An attempt is made to construct a semigroup generalization of the relativistic invariance principle for transformation between inertial and arbitrary non-inertial coordinates.
Preface
It is convenient to express the motion of the non-inertial observer by means of her proper acceleration because this quantity is directly observable and makes no reference to external inertial frames. Following this strategy the non-inertial observer metric is expected to depend on the proper acceleration history of the non-inertial observer. We shall be particularly concerned with what can be actually measured by the non-inertial observer, and our construction will depend on an observable definition of the coordinates (radar coordinates) and on an observable
and intrinsic description of the non-inertial observer motion (the proper acceleration).
As mentioned, the non-inertial observer can construct coordinates using different methods. The transformation between inertial and non-inertial coordinates should reduce to a Lorentz transformation if the observer has
vanishing acceleration. However, this requirement is too weak to determine a unique solution. There are at least three possibilities that have been considered: radar coordinates,[1],[2],[3],[4] Fermi coordinates[5],[6],[7],[8] and Møller coordinates [9],[10],[11],[12],[13],[14].
http://www.astronomy.ru/forum/index.php/topic,36598.0.html
http://phorum.lebedev.ru/viewtopic.php?t=1615&sid=b316d82ece1238de2fad5ffed84...