# xTras: A field-theory inspired xAct package for mathematica

## Description

This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract We present the tensor computer algebra package xTras, which provides functions and methods frequently needed when doing (classical) field theory. Amongst others, it can compute contractions, make Ansätze, and solve tensorial equations. It is built upon the tensor computer algebra system xAct, a collection of packages for Mathematica. Title of program: xTras Catalogue Id: AESH_v1_0 Nature of problem Common problems in classical field theory: making Ansätze, computing contractions, solving tensorial equations, etc. Versions of this program held in the CPC repository in Mendeley Data AESH_v1_0; xTras; 10.1016/j.cpc.2014.02.006