On $\tau_q$-projectivity and $\tau_q$-simplicity

Abstract

In this paper, we first introduce and study the notion of $\tau_q$-projective modules via strongly Lucas modules, and then investigate the $\tau_q$-global dimension $\tau_q$-\gld$(R)$ of a ring $R$. We obtain that if $R$ is a $\tau_q$-Noetherian ring, then $\tau_q$-\gld$(R)=\tau_q$-\gld$(R[x])=$\gld$({\rm T}(R[x]))$. Finally, we study the rings over which all modules are $\tau_q$-projective (i.e., $\tau_q$-semisimple rings). In particular, we show that a ring $R$ is a $\tau_q$-semisimple ring if and only if ${\rm T}(R[x])$ (or ${\rm T}(R)$, or $\mathcal{Q}_0(R)$) is a semisimple ring, if and only if $R$ is a reduced ring with ${\rm Min}(R)$ finite, if and only if every reg-injective (or semireg-injective, or Lucas, or strongly Lucas) module is injective.