A package for computation with indexed objects
within Mathematica and
its applications to metric gravity theories

Sergei A. Klioner

Lorhmann Observatorium, Dresden Technical University,
Mommsenstraße 13, D-01062 Dresden, Germany

EinS is a package for Mathematica intended for calculations with indexed objects (e.g., tensors). The package automatically handles Einstein's summation notation, generates dummy indices, enables one to define new indexed objects and assign symmetries to that objects. EinS has an efficient simplification algorithm based on pattern matching technique which takes full account for symmetries of the objects and the possibility to rename dummy indices. Other important features of EinS are the ability to perform automatically "3+1" split of implicit summations, printing expressions in a natural 2-dimensional form and exporting into plain TEX or LATEX with user-controllable alignment commands.

Several typical applications of EinS are described: computation of the Landau-Lifshits pseudotensor in a rotating reference system, the problem of constructing of a local reference system of a massive extended body in the framework of the parametrized post-Newtonian formalism.


IMACS ACA'98 Electronic Proceedings