• Communications of the Korean Mathematical Society
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• v.17 no.3
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• pp.451-457
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• 2002

Let (R, m, k) be a maximal commutative k-subalgebra of M$\sub$n/(k) where the index of nilpotency i(m) of m is 3. If the socle of R is of special case, then we can construct some isomorphic maximal commutative subalgebras.

• Communications of the Korean Mathematical Society
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• v.15 no.3
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• pp.453-467
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• 2000

For any S-flat module RM(which will be called endoflat) with a commutaitve ring R with identity, where S is the endomorphism ring RM, the fact that every epimorphism is an automorphism has been proved and the Jacobson Radical Rad(S) of S is described as follow; Rad(S) = { f$\in$S｜Imf=Mf is small in M} = {f$\in$S｜Imf $\leq$Rad(M)}. Additionally for any quasi-injective endo-flat module RM, the fact that every monomorphism is an automorphism has been proved and the Jacobson Radical Rad(S) for any quasi-injective endo-flat module has been studied too. Also some equivalent conditions for the semi-primitivity of any faithful endo-flat module RM with the open Jacobson Radical Rad(M) and those for the semi-simplicity of any faithful endo-flat quasi-injective module RM with the closed Socle Soc(M) have been studied.

• East Asian mathematical journal
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• v.16 no.1
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• pp.33-48
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• 2000

In this paper, for any ring R with an identity, in order to study prime ideals of the endomorphism ring $End_R$(M) of left R-module $_RM$, meet-prime submodules, prime radical, sum-prime submodules and the prime socle of a module are defined. Some relations of the prime radical, the prime socle of a module and the prime radical of the endomorphism ring of a module are investigated. It is revealed that meet-prime(or sum-prime) modules and semi-meet-prime(or semi-sum-prime) modules have their prime, semi-prime endomorphism rings, respectively.

• Journal of applied mathematics & informatics
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• v.11 no.1_2
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• pp.317-326
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• 2003

We classify all possible level Artinian O-sequences of socle degree 5 and type 3. Moreover, we show how to construct level Artinian algebras with those Hilbert functions using the sum of two ideals of finite sets of points in $P^2$ such that the ideal of the union of two sets is level.

• Journal of the Korean Mathematical Society
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• v.28 no.1
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• pp.13-21
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• 1991

• Honam Mathematical Journal
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• v.38 no.2
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• pp.259-267
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• 2016

A module M over an associative ring R with unity is a QTAG-module if every finitely generated submodule of any homomorphic image of M is a direct sum of uniserial modules. Recently, the authors introduced the classes of QTAG-modules namely as socle-regular and strongly socle-regular QTAG-modules which properly contain the classes of transitive and fully transitive QTAG-modules respectively. Here we define strongly and quasi transitivities and study the inter relations between various type of transitivities.

• Kyungpook Mathematical Journal
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• v.50 no.1
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• pp.101-107
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• 2010

A module M is said to satisfy the $EC_{11}$ condition if every ec-submodule of M has a complement which is a direct summand. We show that for a multiplication module over a commutative ring the $EC_{11}$ and P-extending conditions are equivalent. It is shown that the $EC_{11}$ property is not inherited by direct summands. Moreover, we prove that if M is an $EC_{11}$-module where SocM is an ec-submodule, then it is a direct sum of a module with essential socle and a module with zero socle. An example is given to show that the reverse of the last result does not hold.

• Bulletin of the Korean Mathematical Society
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• v.56 no.1
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• pp.179-186
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• 2019

This article mainly concentrates on the open question whether a right self-injective ring R is necessary QF if $R/S_l$ is left Goldie. It is answered affirmatively under the condition $S_l{\subseteq}S_r$, where $S_l$ and $S_r$ denote the left socle and right socle of R respectively. And the original condition "right self-injective" can be weakened to "right CS and right P-injective". It is also proved that a semiperfect, left and right mininjective ring R is QF if $S_r{\subseteq}^{ess}$ $R_R$ and $R/S_l$ is left Goldie.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.507-512
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• 2005

We find a condition that a graded Artinian O-sequence of codimension 4 is not level.

• Korean Journal of Mathematics
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• v.7 no.2
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• pp.291-299
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• 1999

Let ${\Omega}$ be the set of all commutative $k$-subalgebras of 14 by 14 matrices over a field $k$ whose dimension is 13 and index of Jacobson radical is 3. Then we will find the equivalent condition for a commutative subalgebra to be maximal.