Published online by Cambridge University Press: 20 November 2018
This article studies algebras $R$ over a simple artinian ring $A$, presented by a quiver and relations and graded by a semigroup $\Sigma $. Suitable semigroups often arise from a presentation of $R$. Throughout, the algebras need not be finite dimensional. The graded ${{K}_{0}}$, along with the $\Sigma $-graded Cartan endomorphisms and Cartan matrices, is examined. It is used to study homological properties.
A test is found for finiteness of the global dimension of a monomial algebra in terms of the invertibility of the Hilbert $\Sigma $-series in the associated path incidence ring.
The rationality of the $\Sigma $-Euler characteristic, the Hilbert $\Sigma $-series and the Poincaré-Betti $\Sigma $-series is studied when $\Sigma $ is torsion-free commutative and $A$ is a division ring. These results are then applied to the classical series. Finally, we find new finite dimensional algebras for which the strong no loops conjecture holds.