Hochschild cohomology, finiteness conditions and a generalisation of $d$-Koszul algebras

Abstract

Given a finite-dimensional algebra $\Lambda$ and $A \geqslant 1$, we construct a new algebra $\tilde{\Lambda}_A$, called the stretched algebra, and relate the homological properties of $\Lambda$ and $\tilde{\Lambda}_A$. We investigate Hochschild cohomology and the finiteness condition (Fg), and use stratifying ideals to show that $\Lambda$ has (Fg) if and only if $\tilde{\Lambda}_A$ has (Fg). We also consider projective resolutions and apply our results in the case where $\Lambda$ is a $d$-Koszul algebra for some $d \geqslant 2$.