“…Actions of crossed modules of different structures have also been described in terms of equations, as it can be checked in [10] for crossed modules of groups, in [8], [11] or [31] for crossed modules of Lie algebras, and in [7] for crossed modules of Leibniz algebras. Bearing those examples in mind, it is seemingly reasonable to address the problem by following the next steps: firstly, we consider a homomorphism from (M, P, η) to Act(L, D, µ) = (Tetra(D, L), Tetra(L, D, µ), ∆), and translate into equations every property satisfied by that homomorphism.…”