The paper “Double-copying self-dual Yang-Mills theory to self-dual gravity on twistor space“, co-authored by L. Borsten (Hertfordshire), B. Jurco (Charles University, Prague), H. Kim (Heriot-Watt), T. Macrelli (ETH Zurich), C. Saemann (Heriot-Watt), and Martin Wolf, has been published in the Journal of High Energy Physics. The published version is open access and freely available (link here). The paper constructs a simple Lorentz-invariant action for maximally supersymmetric self-dual Yang-Mills theory that manifests colour-kinematics duality. The screenshot below captures the paragraph on graded Lie algebras in Section 3 of the paper.