Frontiers of Mathematics in China

ISSN 1673-3452

ISSN 1673-3576(Online)

CN 11-5739/O1

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, Volume 10 Issue 3

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RESEARCH ARTICLE
Jordan tori for a torsion free abelian group
Saeid AZAM,Yoji YOSHII,Malihe YOUSOFZADEH
Front. Math. China. 2015, 10 (3): 477-509.  
https://doi.org/10.1007/s11464-014-0414-2

Abstract   PDF (298KB)

We classify Jordan G-tori, where G is any torsion-free abelian group. Using the Zelmanov prime structure theorem, such a class divides into three types, the Hermitian type, the Clifford type, and the Albert type. We concretely describe Jordan G-tori of each type.

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Extensions of n-Hom Lie algebras
Ruipu BAI,Ying LI
Front. Math. China. 2015, 10 (3): 511-522.  
https://doi.org/10.1007/s11464-014-0372-8

Abstract   PDF (124KB)

n-Hom Lie algebras are twisted by n-Lie algebras by means of twisting maps. n-Hom Lie algebras have close relationships with statistical mechanics and mathematical physics. The paper main concerns structures and representations of n-Hom Lie algebras. The concept of nρ-cocycle for an n-Hom Lie algebra (G, [,… , ], α) related to a G-module (V, ρ, β) is proposed, and a sufficient condition for the existence of the dual representation of an n-Hom Lie algebra is provided. From a G-module (V, ρ, β) and an nρ-cocycle θ, an n-Hom Lie algebra (Tθ(V ), [, … , ]θ, γ) is constructed on the vector space Tθ(V ) = G⊕V, which is called the Tθ-extension of an n-Hom Lie algebra (G, [, … , ], α) by the G-module (V, ρ, β).

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Bicomplex Hermitian Clifford analysis
Lin CHEN,Guangbin REN,Haiyan WANG
Front. Math. China. 2015, 10 (3): 523-546.  
https://doi.org/10.1007/s11464-015-0410-1

Abstract   PDF (192KB)

Complex Hermitian Clifford analysis emerged recently as a refinement of the theory of several complex variables, while at the same time, the theory of bicomplex numbers motivated by the bicomplex version of quantum mechanics is also under full development. This stimulates us to combine the Hermitian Clifford analysis with the theory of bicomplex number so as to set up the theory of bicomplex Hermitian Clifford analysis. In parallel with the Euclidean Clifford analysis, the bicomplex Hermitian Clifford analysis is centered around the bicomplex Hermitian Dirac operator |D:C(R4n,W4n)C(R4n,W4n), where W4n is the tensor product of three algebras, i.e., the hyperbolic quaternion B^, the bicomplex number B, and the Clifford algebra Rn. The operator D is a square root of the Laplacian in R4n, introduced by the formula D|=j=03Kj?Zj with Kjbeing the basis of B^, and ?Zj denoting the twisted Hermitian Dirac operators in the bicomplex Clifford algebra B?R0,4n whose definition involves a delicate construction of the bicomplexWitt basis. The introduction of the operator D can also overturn the prevailing opinion in the Hermitian Clifford analysis in the complex or quaternionic setting that the complex or quaternionic Hermitiean monogenic functions are described by a system of equations instead of by a single equation like classical monogenic functions which are null solutions of Dirac operator. In contrast to the Hermitian Clifford analysis in quaternionic setting, the Poisson brackets of the twisted real Clifford vectors do not vanish in general in the bicomplex setting. For the operator D, we establish the Cauchy integral formula, which generalizes the Martinelli-Bochner formula in the theory of several complex variables.

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Map composition generalized to coherent collections of maps
Herng Yi CHENG,Kang Hao CHEONG
Front. Math. China. 2015, 10 (3): 547-565.  
https://doi.org/10.1007/s11464-015-0435-5

Abstract   PDF (180KB)

Relation algebras give rise to partial algebras on maps, which are generalized to partial algebras on polymaps while preserving the properties of relation union and composition. A polymap is defined as a map with every point in the domain associated with a special set of maps. Polymaps can be represented as small subcategories of Set?, the category of pointed sets. Map composition and the counterpart of relation union for maps are generalized to polymap composition and sum. Algebraic structures and categories of polymaps are investigated. Polymaps present the unique perspective of an algebra that can retain many of its properties when its elements (maps) are augmented with collections of other elements.

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Zagreb indices of graphs
Kinkar Ch. DAS,Kexiang XU,Junki NAM
Front. Math. China. 2015, 10 (3): 567-582.  
https://doi.org/10.1007/s11464-015-0431-9

Abstract   PDF (149KB)

The first Zagreb index M1(G) is equal to the sum of squares of the degrees of the vertices, and the second Zagreb index M2(G) is equal to the sum of the products of the degrees of pairs of adjacent vertices of the underlying molecular graph G. In this paper, we obtain lower and upper bounds on the first Zagreb index M1(G) of G in terms of the number of vertices (n), number of edges (m), maximum vertex degree (Δ), and minimum vertex degree (δ). Using this result, we find lower and upper bounds on M2(G). Also, we present lower and upper bounds on M2(G) +M2(G) in terms of n, m, Δ, and δ, where G denotes the complement of G. Moreover, we determine the bounds on first Zagreb coindex M1(G) and second Zagreb coindex M2(G). Finally, we give a relation between the first Zagreb index and the second Zagreb index of graph G.

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Reilly-type inequalities for p-Laplacian on compact Riemannian manifolds
Feng DU,Jing MAO
Front. Math. China. 2015, 10 (3): 583-594.  
https://doi.org/10.1007/s11464-015-0422-x

Abstract   PDF (139KB)

For a compact Riemannian manifold M immersed into a higher dimensional manifold which can be chosen to be a Euclidean space, a unit sphere, or even a projective space, we successfully give several upper bounds in terms of the norm of the mean curvature vector of M for the first non-zero eigenvalue of the p-Laplacian (1<p<+) on M. This result can be seen as an extension of Reilly’s bound for the first non-zero closed eigenvalue of the Laplace operator.

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Stochastic Volterra equations driven by fractional Brownian motion
Xiliang FAN
Front. Math. China. 2015, 10 (3): 595-620.  
https://doi.org/10.1007/s11464-015-0413-y

Abstract   PDF (225KB)

This paper is devoted to study a class of stochastic Volterra equations driven by fractional Brownian motion. We first prove the Driver type integration by parts formula and the shift Harnack type inequalities. As a direct application, we provide an alternative method to describe the regularities of the law of the solution. Secondly, by using the Malliavin calculus, the Bismut type derivative formula is established, which is then applied to the study of the gradient estimate and the strong Feller property. Finally, we establish the Talagrand type transportation cost inequalities for the law of the solution on the path space with respect to both the uniform metric and the L2-metric.

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Bipartite double cover and perfect 2-matching covered graph with its algorithm
Zhiyong GAN,Dingjun LOU,Zanbo ZHANG,Xuelian WEN
Front. Math. China. 2015, 10 (3): 621-634.  
https://doi.org/10.1007/s11464-015-0449-z

Abstract   PDF (146KB)

Let B(G) denote the bipartite double cover of a non-bipartite graph G with v≥2 vertices and ? edges. We prove that G is a perfect 2-matching covered graph if and only if B(G) is a 1-extendable graph. Furthermore, we prove that B(G) is a minimally 1-extendable graph if and only if G is a minimally perfect 2-matching covered graph and for each e = xyE(G), there is an independent set S in G such that |ΓG(S)| = |S| + 1, x S and |ΓG-xy(S) | = |S|. Then, we construct a digraph D from B(G) or G and show that D is a strongly connected digraph if and only if G is a perfect 2-matching covered graph. So we design an algorithm in O(v?) time that determines whether G is a perfect 2-matching covered graph or not.

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Termination of algorithm for computing relative Gr?bner bases and difference differential dimension polynomials
Guanli HUANG,Meng ZHOU
Front. Math. China. 2015, 10 (3): 635-648.  
https://doi.org/10.1007/s11464-015-0439-1

Abstract   PDF (159KB)

We introduce the concept of difference-differential degree compatibility on generalized term orders. Then we prove that in the process of the algorithm the polynomials with higher and higher degree would not be produced, if the term orders ‘?’ and ‘?’ are difference-differential degree compatibility. So we present a condition on the generalized orders and prove that under the condition the algorithm for computing relative Gr?bner bases will terminate. Also the relative Gr?bner bases exist under the condition. Finally, we prove the algorithm for computation of the bivariate dimension polynomials in difference-differential modules terminates.

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Solving sparse non-negative tensor equations: algorithms and applications
Xutao LI, Michael K. NG
Front. Math. China. 2015, 10 (3): 649-680.  
https://doi.org/10.1007/s11464-014-0377-3

Abstract   PDF (732KB)

We study iterative methods for solving a set of sparse non-negative tensor equations (multivariate polynomial systems) arising from data mining applications such as information retrieval by query search and community discovery in multi-dimensional networks. By making use of sparse and non-negative tensor structure, we develop Jacobi and Gauss-Seidel methods for solving tensor equations. The multiplication of tensors with vectors are required at each iteration of these iterative methods, the cost per iteration depends on the number of non-zeros in the sparse tensors. We show linear convergence of the Jacobi and Gauss-Seidel methods under suitable conditions, and therefore, the set of sparse non-negative tensor equations can be solved very efficiently. Experimental results on information retrieval by query search and community discovery in multi-dimensional networks are presented to illustrate the application of tensor equations and the effectiveness of the proposed methods.

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Conditional mean convergence theorems of conditionally dependent random variables under conditions of integrability
Xinghui WANG,Shuhe HU
Front. Math. China. 2015, 10 (3): 681-696.  
https://doi.org/10.1007/s11464-015-0450-6

Abstract   PDF (154KB)

We give the conditionally residual h-integrability with exponent r for an array of random variables and establish the conditional mean convergence of conditionally negatively quadrant dependent and conditionally negative associated random variables under this integrability. These results generalize and improve the known ones.

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Completable nilpotent Lie superalgebras
Mingzhong WU
Front. Math. China. 2015, 10 (3): 697-713.  
https://doi.org/10.1007/s11464-014-0362-x

Abstract   PDF (148KB)

We discuss a class of filiform Lie superalgebras Ln,m. From these Lie superalgebras, all the other filiform Lie superalgebras can be obtained by deformations. We have decompositions of Der0ˉ(Ln,m) and Der1 (Ln,m). By computing a maximal torus on each Ln,m, we show that Ln,m are completable nilpotent Lie superalgebras. We also view Ln,m as Lie algebras, prove that Ln,m are of maximal rank, and show that Ln,m are completable nilpotent Lie algebras. As an application of the results, we show a Heisenberg superalgebra is a completable nilpotent Lie superalgebra.

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12 articles