Let G be a discrete group and (G, G+) an ordered group. Let (G, GF) be the minimal quasiordered group containing (G, G+). Let G+ (G) and (G) be the corresponding Toeplitz algebras, and γGF,G+ the natural C*-algebra m...Let G be a discrete group and (G, G+) an ordered group. Let (G, GF) be the minimal quasiordered group containing (G, G+). Let G+ (G) and (G) be the corresponding Toeplitz algebras, and γGF,G+ the natural C*-algebra morphism from G+ (G) to GF(G). This paper studies the connection between Ker GF,G+ and the minimal closed ideal ofTG+ (G). It is proved that if G is amenable and GF≠G+, then Ker γGF,G+ is exactly the minimal closed non-trivial ideal of G+ (G). As an application, in the last part of this paper, a character of K-groups of Toeplitz algebras on ordered groups is clarified.展开更多
By a dynamical system we mean a pair of (X,T), whereX is compact Hausdorff space. In this paper we define an adherence semigroupA(X,T--X x, which is the set of all pointwise limit of subnets of(T n)n∈N. We will prove...By a dynamical system we mean a pair of (X,T), whereX is compact Hausdorff space. In this paper we define an adherence semigroupA(X,T--X x, which is the set of all pointwise limit of subnets of(T n)n∈N. We will prove some commonness between adherence semigroup and Ellis semigroup.展开更多
An ordered semiring is a semiring S equipped with a partial order ≤ such that the operations are monotonic and constant 0 is the least element of S.In this paper,several notions,for example,ordered ideal,minimal idea...An ordered semiring is a semiring S equipped with a partial order ≤ such that the operations are monotonic and constant 0 is the least element of S.In this paper,several notions,for example,ordered ideal,minimal ideal,and maximal ideal of an ordered semiring,simple ordered semirings,etc.,are introduced.Some properties of them are given and characterizations for minimal ideals are established.Also,the matrix semiring over an ordered semiring is consid-ered.Partial results obtained in this paper are analogous to the corresponding ones on ordered semigroups,and on the matrix semiring over a semiring.展开更多
We study the structure of a metric n-Lie algebra G over the complex field C. Let G = S＋R be the Levi decomposition, where T4 is the radical of G and S is a strong semisimple subalgebra of G. Denote by re（G） the num...We study the structure of a metric n-Lie algebra G over the complex field C. Let G = S＋R be the Levi decomposition, where T4 is the radical of G and S is a strong semisimple subalgebra of G. Denote by re（G） the number of all minimal ideals of an indecomposable metric n-Lie algebra and R^⊥ the orthogonal complement of R. We obtain the following results. As S-modules, R^⊥ is isomorphic to the dual module of G/R. The dimension of the vector space spanned by all nondegenerate invariant symmetric bilinear forms on G is equal to that of the vector space of certain linear transformations on G; this dimension is greater than or equal to rn（G） ＋ 1. The centralizer of T4 in G is equal to the sum of all minimal ideals; it is the direct sum of R^⊥and the center of G. Finally, G has no strong semisimple ideals if and only if R^⊥ R.展开更多
基金the National Natural Science Foundation of China!(No. 19901019) the YouthScience Foundation of Colleges and Universities o
文摘Let G be a discrete group and (G, G+) an ordered group. Let (G, GF) be the minimal quasiordered group containing (G, G+). Let G+ (G) and (G) be the corresponding Toeplitz algebras, and γGF,G+ the natural C*-algebra morphism from G+ (G) to GF(G). This paper studies the connection between Ker GF,G+ and the minimal closed ideal ofTG+ (G). It is proved that if G is amenable and GF≠G+, then Ker γGF,G+ is exactly the minimal closed non-trivial ideal of G+ (G). As an application, in the last part of this paper, a character of K-groups of Toeplitz algebras on ordered groups is clarified.
文摘By a dynamical system we mean a pair of (X,T), whereX is compact Hausdorff space. In this paper we define an adherence semigroupA(X,T--X x, which is the set of all pointwise limit of subnets of(T n)n∈N. We will prove some commonness between adherence semigroup and Ellis semigroup.
基金Supported by the National Natural Science Foundation of Jiangxi Province (Grant No.2010GZS0093)
文摘An ordered semiring is a semiring S equipped with a partial order ≤ such that the operations are monotonic and constant 0 is the least element of S.In this paper,several notions,for example,ordered ideal,minimal ideal,and maximal ideal of an ordered semiring,simple ordered semirings,etc.,are introduced.Some properties of them are given and characterizations for minimal ideals are established.Also,the matrix semiring over an ordered semiring is consid-ered.Partial results obtained in this paper are analogous to the corresponding ones on ordered semigroups,and on the matrix semiring over a semiring.
基金Supported by National Natural Science Foundation of China (Grant No. 10871192)Natural Science Foundation of Hebei Province, China (Grant No. A2010000194)
文摘We study the structure of a metric n-Lie algebra G over the complex field C. Let G = S＋R be the Levi decomposition, where T4 is the radical of G and S is a strong semisimple subalgebra of G. Denote by re（G） the number of all minimal ideals of an indecomposable metric n-Lie algebra and R^⊥ the orthogonal complement of R. We obtain the following results. As S-modules, R^⊥ is isomorphic to the dual module of G/R. The dimension of the vector space spanned by all nondegenerate invariant symmetric bilinear forms on G is equal to that of the vector space of certain linear transformations on G; this dimension is greater than or equal to rn（G） ＋ 1. The centralizer of T4 in G is equal to the sum of all minimal ideals; it is the direct sum of R^⊥and the center of G. Finally, G has no strong semisimple ideals if and only if R^⊥ R.
