scholarly journals Characterization of the endomorphism rings of divisible torsion modules and reduced complete torsion-free modules over complete discrete valuation rings

1971 ◽  
Vol 37 (1) ◽  
pp. 141-170 ◽  
Author(s):  
Wolfgang Liebert
Keyword(s):  
Endomorphism Rings ◽  
Discrete Valuation Rings ◽  
Valuation Rings ◽  
Free Modules ◽  
Torsion Modules ◽  
Torsion Free

scholarly journals Proper classes generated by τ- closed submodules

2019 ◽  
Vol 27 (3) ◽  
pp. 83-95
Author(s):  
Yılmaz Durğun ◽  
Ayşe Çobankaya
Keyword(s):  
Proper Class ◽  
Closed Submodules ◽  
Free Modules ◽  
Torsion Modules ◽  
Exact Sequences ◽  
Torsion Free

AbstractThe main object of this paper is to study relative homological aspects as well as further properties of τ -closed submodules. A submodule N of a module M is said to be τ -closed (or τ -pure) provided that M/N is τ -torsion-free, where τ stands for an idempotent radical. Whereas the well-known proper class 𝒞losed (𝒫ure) of closed (pure) short exact sequences, the class τ −𝒞losed of τ -closed short exact sequences need not be a proper class. We describe the smallest proper class 〈τ − 𝒞losed〉 containing τ − 𝒞losed, through τ -closed submodules. We show that the smallest proper class 〈τ − 𝒞losed〉 is the proper classes projectively generated by the class of τ -torsion modules and coprojectively generated by the class of τ -torsion-free modules. Also, we consider the relations between the proper class 〈τ − 𝒞losed〉 and some of well-known proper classes, such as 𝒞losed, 𝒫ure.

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