  The sum-rank metric arises as an algebraic approach for coding in MIMO
block-fading channels and multishot network coding. Codes designed in the
sum-rank metric have raised interest in applications such as streaming codes,
robust coded distributed storage systems and post-quantum secure cryptosystems.
The sum-rank metric can be seen as a generalization of the well-known Hamming
metric and the rank metric. As a relatively new metric, there are still many
open theoretical problems for codes in the sum-rank metric. In this paper we
investigate the geometrical properties of the balls with sum-rank radii
motivated by investigating covering properties of codes.
