“…Including the information of the determinant of invariant vectors yields a partial description of ω 2 , enough to describe the Killing form of the Automorphic Lie Algebra and its abelianisation (as well as κ i = 1 2 α∈Φ ω 2 (α, −α)). Moreover, it shows that ω 2 can only take two values, thereby reproducing isomorphisms obtained in [27,28,29,2,22,24]. The challenge remains to find the complete description of ω 2 , and hence the Automorphic Lie Algebra, from the embedding of the reduction group into Aut(g).…”