Nakayama (Ann. of Math. 42, 1941) showed that over an artinian serial ring every module is a direct sum of uniserial modules. Hence artinian serial rings have the property that each right (left) ideal is a finite direct sum of quasi-injective right (left) ideals. A ring with the property that each right (left) ideal is a finite direct sum of quasi-injective right (left) ideals will be called a ...

In act theory, Pseudo injective acts and their generalizations are essential. As a result, the purpose of this work is to give generalization pseudo quasi principally specifically small acts. Besides, concept was presented, which can be employed later. If each S-monomorphism from M-cyclic sub-act M\textsubscript{S} N\textsubscript{S} extended S-homomorphism N\textsubscript{S}, An S-act called p...

Let k be a field. Given two finite-dimensional right comodules N andM over a k–coalgebra C, the k–vector spaces ExtC(N,M) need not to be finite-dimensional. This is due to the fact that the injective right comodules appearing in the minimal injective resolution of M need not to be of finite dimension or even quasi-finite. The obstruction here is that factor comodules of quasi-finite comodules a...

A realization of a graph G is pair (G,p) where p maps the vertices into Euclidean space Rd. The injective if and quasi-injective for each edge G, endpoints to different points in space. globally rigid any (G,q) Rd with same lengths congruent (G,p). In this paper we characterize graphs that have an (quasi-injective, respectively) non-globally R1, show problem recognizing these NP-complete both c...

In this paper we show that a direct decomposition of modules M N, with N homologically independent to the inJective hull of H, is a CS-module if and only if N is injective relative to H and both of M and N are CS-modules. As an application, we prove that a direct sum of a non-singular semisimple module and a quasi-continuous module with zero socle is quasi-continuous. This result is known for q...

In this paper we show that a direct decomposition of modules M N, with N homologically independent to the inJective hull of H, is a CS-module if and only if N is injective relative to H and both of M and N are CS-modules. As an application, we prove that a direct sum of a non-singular semisimple module and a quasi-continuous module with zero socle is quasi-continuous. This result is known for q...