In this article,we introduce and study the class of approximately Artinian(Noetherian)C^(*)-algebras,called AR-algebras(AN-algebras),which is a simultaneous generalization of Artinian(Noetherian)C*-algebras and AF-alg...In this article,we introduce and study the class of approximately Artinian(Noetherian)C^(*)-algebras,called AR-algebras(AN-algebras),which is a simultaneous generalization of Artinian(Noetherian)C*-algebras and AF-algebras.We study properties such as the ideal property and topological dimension zero for them.In particular,we show that a faithful AR or AN algebra is strongly purely infinite iff it is purely infinite iff it is weakly purely infinite.This extends the Kirchberg's O_(∞)-absorption theorem,and implies that a weakly purely infinite C^(*)-algebra is Noetherian iff every its ideal has a full projection.展开更多
Let R be a simple Artinian ring,M<sub>m×n</sub>（R） be the set of all m×n matrices over R.GL<sub>n</sub>（R） be the set of all n×n invertible matrices over R.Let A<sup>T&...Let R be a simple Artinian ring,M<sub>m×n</sub>（R） be the set of all m×n matrices over R.GL<sub>n</sub>（R） be the set of all n×n invertible matrices over R.Let A<sup>T</sup> be the transpose matrix ofA∈M<sub>m×n</sub>（R）.By the Wedderburn-Artin theorem,R be isomorphic to a total matrix ringM<sub>s×s</sub>（D） over a division ring D.Let α→（α）<sub>D</sub> be an isomorphism of R onto M<sub>s×s</sub>（D）, if展开更多
Let (?) be a formation locally defined by f(P), G ∈ (?) and A a ZG-module, where p ∈ π = { all primes and symbol ∞}. Then a p-main-factor U/V of G is said to be (?)-central in G if G/CG(U/V) ∈f(p). In this paper,...Let (?) be a formation locally defined by f(P), G ∈ (?) and A a ZG-module, where p ∈ π = { all primes and symbol ∞}. Then a p-main-factor U/V of G is said to be (?)-central in G if G/CG(U/V) ∈f(p). In this paper, we have proved that: let (?) be a locally defined formation consisting of locally soluble groups, G a hyper-(cyclic or finite) locally soluble group and A an artinian ZG-module with all irreducible ZG-factors of A being finite; if G ∈ (?), f(∞) ≡ f(p) . f(p)≠φ for each p ∈ π, A has an (?)-decomposition.展开更多
Let （R,m） be a Noetherian local ring. Denote by N-dimnA the Noetherian dimension of an Artinian R-module A. In this paper, we give some characterizations for the ring R to satisfy N-dimRA = dim（R/AnnRA） for certai...Let （R,m） be a Noetherian local ring. Denote by N-dimnA the Noetherian dimension of an Artinian R-module A. In this paper, we give some characterizations for the ring R to satisfy N-dimRA = dim（R/AnnRA） for certain Artinian R-modules A. Then the existence of a co-localization compatible with Artinian R-modules is studied and it is shown that if it is compatible with local cohomologies of finitely generated modules, then the base ring is universally catenary and all of its formal fibers are Cohen-Macaulay.展开更多
Let a be an ideal of a local ring （R, m） and A4 a finitely generated R-modu｜e. In this paper we study the Artinianness properties of formal local cohomology modules and we obtain the lower and upper bounds for Arti...Let a be an ideal of a local ring （R, m） and A4 a finitely generated R-modu｜e. In this paper we study the Artinianness properties of formal local cohomology modules and we obtain the lower and upper bounds for Artinianness of formal local cohomology modules. Additionally, we determine the set AttR a dim M（M） and we show that the set of all non-isomorphic formal local cohomology modules a dim M（M） is finite.展开更多
In this paper, a necessary and sufficient condition is given for a commutative Artinian local ring whose annihilating-ideal graph is a star graph. Also, a complete char- acterization is established for a finite local ...In this paper, a necessary and sufficient condition is given for a commutative Artinian local ring whose annihilating-ideal graph is a star graph. Also, a complete char- acterization is established for a finite local ring whose annihilating-ideal graph is a star graph.展开更多
Let (A,m) be a commutative quasi-local ring with non-zero identity and M be an Artinian A-module with dim M = d. If I is an ideal of A with l(0 :m I)<∞, then we show that for a minimal reduction J of I,(0 : m JI)=...Let (A,m) be a commutative quasi-local ring with non-zero identity and M be an Artinian A-module with dim M = d. If I is an ideal of A with l(0 :m I)<∞, then we show that for a minimal reduction J of I,(0 : m JI)=(0 :m I^2) if and only if l(0:M I^n+1)=l(0:m J)^(n+d/d)-l(0 :M J)/(0 :M I))(n+d-1/d-1) for all n≥> 0. Moreover, we study the dual of Burch's inequality. In particular, the Burch's inequality becomes an equality if G(I,M) is co-Cohen-Macaulay.展开更多
Let R = ⊙n〉0 Rn be a standard graded ring, a ∩ ⊙n〉0 Rn an ideal of R, and M, N two finitely generated graded R-modules. This paper studies the homogeneous components of graded generalized local cohomology modules...Let R = ⊙n〉0 Rn be a standard graded ring, a ∩ ⊙n〉0 Rn an ideal of R, and M, N two finitely generated graded R-modules. This paper studies the homogeneous components of graded generalized local cohomology modules. We show that for any i 〉 0, the n-th graded component Hiα（M, N）n of the i-th generalized local cohomology module of M and N with respect to a vanishes for all n 〉〉 0. Some sufficient conditions are pro- posed to satisfy the equality sup{end（Hiα （M, N）） [ i _〉 0} = sup{end（HiR＋ （M, N）） ｜ i 〉 0}. Also, some sufficient conditions are proposed for the tameness of Hiα（M, N） such that i = fRα＋（M,N） or i = cdα（M,g）, where fRα＋（M,N） and cdα（M,g） denote the R＋- finiteness dimension and the cohomological dimension of M and N with respect to a, respectively. Finally, we consider the Artinian property of some submodules and quotient modules of Hjα（M, N）, where j is the first or last non-minimax level of Hiα（M, N）.展开更多
Let （R, m） be a commutative Noetherian local ring, I an ideal of R and M a finitely generated R-module. Let limnHm^i（M/I^nM）be the ith formal local cohomology module of M with respect to I.In this paper, we discus...Let （R, m） be a commutative Noetherian local ring, I an ideal of R and M a finitely generated R-module. Let limnHm^i（M/I^nM）be the ith formal local cohomology module of M with respect to I.In this paper, we discuss some properties of formal local cohomology modules limnHm^i（M/I^nM）,which are analogous to the finiteness and Artinianness of local cohomology modules of a finitely generated module.展开更多
In this paper we define and study chain conditions for Hilbert C＊-modules through their C＊-algebras of compact operators and discuss their perseverance under Morita equivalence and tensor products. We show that thes...In this paper we define and study chain conditions for Hilbert C＊-modules through their C＊-algebras of compact operators and discuss their perseverance under Morita equivalence and tensor products. We show that these chain conditions are passed from the C＊-algebra to its Hilbert module under certain conditions. We also study chain conditions for Hilbert modules coming from inclusion of C＊-algebra with a faithful conditional expectation.展开更多
基金supported by grants from INSF(98029498,99013953)partly supported by a grant from IPM(96430215)。
文摘In this article,we introduce and study the class of approximately Artinian(Noetherian)C^(*)-algebras,called AR-algebras(AN-algebras),which is a simultaneous generalization of Artinian(Noetherian)C*-algebras and AF-algebras.We study properties such as the ideal property and topological dimension zero for them.In particular,we show that a faithful AR or AN algebra is strongly purely infinite iff it is purely infinite iff it is weakly purely infinite.This extends the Kirchberg's O_(∞)-absorption theorem,and implies that a weakly purely infinite C^(*)-algebra is Noetherian iff every its ideal has a full projection.
基金Supported by the NSF of Hunan Provincethe Science and Technology Development Foundation of Xiangtan Polytechnic University
文摘Let R be a simple Artinian ring,M<sub>m×n</sub>（R） be the set of all m×n matrices over R.GL<sub>n</sub>（R） be the set of all n×n invertible matrices over R.Let A<sup>T</sup> be the transpose matrix ofA∈M<sub>m×n</sub>（R）.By the Wedderburn-Artin theorem,R be isomorphic to a total matrix ringM<sub>s×s</sub>（D） over a division ring D.Let α→（α）<sub>D</sub> be an isomorphism of R onto M<sub>s×s</sub>（D）, if
文摘Let (?) be a formation locally defined by f(P), G ∈ (?) and A a ZG-module, where p ∈ π = { all primes and symbol ∞}. Then a p-main-factor U/V of G is said to be (?)-central in G if G/CG(U/V) ∈f(p). In this paper, we have proved that: let (?) be a locally defined formation consisting of locally soluble groups, G a hyper-(cyclic or finite) locally soluble group and A an artinian ZG-module with all irreducible ZG-factors of A being finite; if G ∈ (?), f(∞) ≡ f(p) . f(p)≠φ for each p ∈ π, A has an (?)-decomposition.
文摘Let （R,m） be a Noetherian local ring. Denote by N-dimnA the Noetherian dimension of an Artinian R-module A. In this paper, we give some characterizations for the ring R to satisfy N-dimRA = dim（R/AnnRA） for certain Artinian R-modules A. Then the existence of a co-localization compatible with Artinian R-modules is studied and it is shown that if it is compatible with local cohomologies of finitely generated modules, then the base ring is universally catenary and all of its formal fibers are Cohen-Macaulay.
文摘Let a be an ideal of a local ring （R, m） and A4 a finitely generated R-modu｜e. In this paper we study the Artinianness properties of formal local cohomology modules and we obtain the lower and upper bounds for Artinianness of formal local cohomology modules. Additionally, we determine the set AttR a dim M（M） and we show that the set of all non-isomorphic formal local cohomology modules a dim M（M） is finite.
基金The first author is supported by Fundamental Research Funds for the Central Universi- ties （No. XDJK2013C060）, Chongqing Research Program of Application Foundation and Advanced Technology （No. cstc2014jcyjA00028） and Scientific Research Foundation for Doctors of Southwest University （No. SWUl12054）. The second author is supported by National Natural Science Foundation of China （No. 11271250）.
文摘In this paper, a necessary and sufficient condition is given for a commutative Artinian local ring whose annihilating-ideal graph is a star graph. Also, a complete char- acterization is established for a finite local ring whose annihilating-ideal graph is a star graph.
文摘Let (A,m) be a commutative quasi-local ring with non-zero identity and M be an Artinian A-module with dim M = d. If I is an ideal of A with l(0 :m I)<∞, then we show that for a minimal reduction J of I,(0 : m JI)=(0 :m I^2) if and only if l(0:M I^n+1)=l(0:m J)^(n+d/d)-l(0 :M J)/(0 :M I))(n+d-1/d-1) for all n≥> 0. Moreover, we study the dual of Burch's inequality. In particular, the Burch's inequality becomes an equality if G(I,M) is co-Cohen-Macaulay.
文摘Let R = ⊙n〉0 Rn be a standard graded ring, a ∩ ⊙n〉0 Rn an ideal of R, and M, N two finitely generated graded R-modules. This paper studies the homogeneous components of graded generalized local cohomology modules. We show that for any i 〉 0, the n-th graded component Hiα（M, N）n of the i-th generalized local cohomology module of M and N with respect to a vanishes for all n 〉〉 0. Some sufficient conditions are pro- posed to satisfy the equality sup{end（Hiα （M, N）） [ i _〉 0} = sup{end（HiR＋ （M, N）） ｜ i 〉 0}. Also, some sufficient conditions are proposed for the tameness of Hiα（M, N） such that i = fRα＋（M,N） or i = cdα（M,g）, where fRα＋（M,N） and cdα（M,g） denote the R＋- finiteness dimension and the cohomological dimension of M and N with respect to a, respectively. Finally, we consider the Artinian property of some submodules and quotient modules of Hjα（M, N）, where j is the first or last non-minimax level of Hiα（M, N）.
基金The NSF (10771152,10926094) of Chinathe NSF (09KJB110006) for Colleges and Universities in Jiangsu Provincethe Research Foundation (Q4107805) of Soochow University and the Research Foundation (Q3107852) of Pre-research Project of Soochow University
文摘Let （R, m） be a commutative Noetherian local ring, I an ideal of R and M a finitely generated R-module. Let limnHm^i（M/I^nM）be the ith formal local cohomology module of M with respect to I.In this paper, we discuss some properties of formal local cohomology modules limnHm^i（M/I^nM）,which are analogous to the finiteness and Artinianness of local cohomology modules of a finitely generated module.
文摘In this paper we define and study chain conditions for Hilbert C＊-modules through their C＊-algebras of compact operators and discuss their perseverance under Morita equivalence and tensor products. We show that these chain conditions are passed from the C＊-algebra to its Hilbert module under certain conditions. We also study chain conditions for Hilbert modules coming from inclusion of C＊-algebra with a faithful conditional expectation.
