2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/132229For each simply-laced Dynkin graph $Δ$ we realize the simple complex Lie algebra of type $Δ$ as a quotient algebra of the complex degenerate composition Lie algebra $L(A)_{1}^{\mathbb{C}}$ of a domestic canonical algebra $A$ of type $Δ$ by some ideal $I$ of $L(A)_{1}^{\mathbb{C}}$ that is defined via the Hall algebra of $A$, and give an explicit form of $I$. Moreover, we show that each root space of $L(A)_{1}^{\mathbb{C}}/I$ has a basis given by the coset of an indecomposable $A$-module $M$ with root easily computed by the dimension vector of $M$.43 pages, 5 figures, revised versionRepresentation Theory16G20text