Subalgebras of rational matrix algebras
Given a finite dimensional algebra \(A\) over the field of rational numbers, the authors investigate certain subalgebras of \(A\) with some universal property. Among others they characterize the finite dimensional semisimple algebras over the rational numbers in terms of the so called quasi-endomorphism rings of Abelian groups and certain projective modules.
scientific article; zbMATH DE number 1336379