One may want to add/contract tensors with indices in the following way :

T["<sup>ijklm_m]+T["</sup>mklij_m"]

This entails to implement

• _get_item_ method
• _set_item_ method
• _add_ method
  which all keep track of the indices names.

CC: @egourgoulhon

Component: linear algebra

Keywords: tensor, contraction, symmetries, tensor with indices

Author: Léo Brunswic

Branch/Commit: a1b9630

Reviewer: Eric Gourgoulhon, Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/28787