2019/12/15 by Lixin Mao, Mao, Lixin · 1 citation
Mathematics · #Algebraic structures and combinatorial models #Advanced Topics in Algebra #Rings, Modules, and Algebras
paper · pdf · doi:10.48550/arxiv.1912.06968
Let T=\biggl(\beginmatrix A&0 U&B \endmatrix\biggr) be a formal triangular matrix ring, where A and B are rings and U is a (B, A)-bimodule. We prove that: (1) If UA and B U have finite flat dimensions, then a left T-module \biggl(\beginmatrix M1 M2\endmatrix\biggr)φM is Ding projective if and only if M1 and M2/\rm im(φM) are Ding projective and the morphism φM is a monomorphism. (2) If T is a right coherent ring, BU has finite flat dimension, UA is finitely presented and has finite projective or FP-injective dimension, then a right T-module (W1, W2)_φW is Ding injective if and only if W1 and ker(\widetildeφW) are Ding injective and the morphism \widetildeφW is an epimorphism. As a consequence, we describe Ding projective and Ding injective dimensions of a T-module.