Mathematical Theory and Applications ›› 2024, Vol. 44 ›› Issue (4): 1-18.doi: 10.3969/j.issn.1006-8074.2024.04.001

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(m,n)-coherent Rings and FP(m,n)-projective Modules

Tan Lingling1 , Zhang Yixia2,*, Zhou Panyue3   

  1. 1. School of Artificial Intelligence, Jianghan University, Wuhan 430056, China;  2. School of Mathematical Sciences, Qufu Normal University, Qufu 273165, China;  3. School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha 410114, China
  • Online:2024-12-28 Published:2025-01-21
  • Contact: Zhang Yixia
  • Supported by:
    This work is supported by the National Natural Science Foundation of China (No. 12471036), the project of Young and Middle-Aged Talents of Hubei Province (No. Q20234405), and the Scientific Research Fund of Hunan Provincial Education Department (No. 24A0221)

Abstract: In this paper, we introduce the notions of $(m,n)$-coherent rings and $FP_{(m,n)}$-projective modules for nonnegative integers $m,n$. We prove that ($\mathcal{FP}_{(m,n)}$-Proj, ($\mathcal{FP}_{n}$-id)$_{\leq m}$) is a complete cotorsion pair for any $m,n\geq 0$ and it is hereditary if and only if the ring $R$ is a left $n$-coherent ring for all $m\geq 0$ and $n\geq 1$. Moreover, we study the existence of $\mathcal{FP}_{(m,n)}$-Proj covers and envelopes and obtain that if $\mathcal{FP}_{(m,n)}$-Proj is closed under pure quotients, then $\mathcal{FP}_{(m,n)}$-Proj is covering for any $n\geq2$. As applications, we obtain that every $R$-module has an epic $\mathcal{FP}_{(m,n)}$-Proj-envelope if and only if the left $FP_{(m,n)}$-global dimension of $R$ is at most 1 and $\mathcal{FP}_{(m,n)}$-Proj is closed under direct products.

Key words: $(m,n)$-coherent ring, $FP_{(m,n)}$-projective module, Cover , Envelope , Cotorsion pair