  By [R. Bautista, P. Gabriel, A.V Roiter., L. Salmeron, Representation-finite
algebras and multiplicative basis. Invent. Math. 81 (1985) 217-285.], a
finite-dimensional algebra having finitely many isoclasses of indecomposable
representations admits a multiplicative basis. In Sections 4.10-4.12 of [P.
Gabriel, A. V. Roiter, Representations of finite-dimensional algebras.
Encyclopaedia of Math. Sci., vol. 73, Algebra 8, Springer-Verlag, 1992] an
analogous hypothesis was formulated for finitely spaced modules over an
aggregate. We prove this conjecture.
