A computational approach to almost-inner derivations

We present a computational approach to determine the space of almost-inner derivations of a finite dimensional Lie algebra given by a structure constant table. We also present an example of a Lie algebra for which the quotient algebra of the almostinner derivations modulo the inner derivations is non-abelian. This answers a question of Kunyavskii and Ostapenko. (c) 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons .org /licenses /by /4 .0/).