Duality of Preenvelopes and Pure InjectiveModules

Huang, Zhaoyong

Canadian mathematical bulletin, Tome 57 (2014) no. 2, pp. 318-325

Résumé

Let $R$ be an arbitrary ring and let ${{\left( - \right)}^{+}}\,=\,\text{Ho}{{\text{m}}_{\mathbb{Z}}}\left( -,\,{\mathbb{Q}}/{\mathbb{Z}}\; \right)$ , where $\mathbb{Z}$ is the ring of integers and $\mathbb{Q}$ is the ring of rational numbers. Let $\mathcal{C}$ be a subcategory of left $R$ -modules and $\mathcal{D}$ a subcategory of right $R$ -modules such that ${{X}^{+}}\,\in \,\mathcal{D}$ for any $X\,\in \,\mathcal{C}$ and all modules in $\mathcal{C}$ are pure injective. Then a homomorphism $f:\,A\to \,C$ of left $R$ -modules with $C\,\in \,\mathcal{C}$ is a $\mathcal{C}$ -(pre)envelope of $A$ provided ${{f}^{+}}:\,{{C}^{+}}\,\to \,{{A}^{+}}$ is a $\mathcal{D}$ -(pre)cover of ${{A}^{+}}$ . Some applications of this result are given.

Détail

DOI : 10.4153/CMB-2013-023-x

Mots-clés : 18G25, 16E30, (pre)envelopes, (pre)covers, duality, pure injective modules, character modules