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.