检索结果-南通市图书馆

On Non-Decomposable Hermitian Forms over Gaussian Domain

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 1998年第4期14卷 447-456页

作者： zhu fuzu, department of mathematics, east china normal university, shanghai 200062, china east china normal university Department of Mathematics Shanghai China (GRID:grid.22069.3f) (ISNI:***)

Methods are presented for the construction of non-decomposable Hermitian forms over the ring of integers of an imaginary quadratic field.

关键词： Non-decomposable form Indecomposable form Odd form Even form Reduced form

CONSTRUCTION OF INDECOMPOSABLEDEFINITE HERMITIAN FORMS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 1994年第3期15卷 349-360页

作者： zhu fuzu (department ofmathematics, east china normal university shanghai 200062,china) 华东师范大学数学系上海 200062

This Paper gives a method to construct indecomposable positive definite integral Hermitianforman imnginary quadratic field Q with gin discriminant and g。n *** is shown that for ally natural numbers n and a, there are n-ary Indecomposable positivedefinite intopal Herlllltian lattices over Q(resp. Q)with discriminant a, exceptfor four(resp. one) exceptions. In these exceptional cases there are no lattices with the desiredproperties.

关键词： Indecomposable lattice(form) Minimum of a lattice(form) Minimal、ctor Irreduclble vector.

ON MATRIX UNITARILY INVARIANT NORM CONDITION NUMBER

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 1998年第2期16卷 121-128页

作者： Dao-sheng Zheng (department of mathematics, east china normal university, shanghai 200062, china) 华东师范大学数学系上海

In this paper, the unitarily invariant norm \\.\\ on C-mxn is used. We first discuss the problem under what case, a rectangular matrix A has minimum condition number K(A) = \\A\\ \\A(+)\\, where A(+) designates the Moore-Penrose inverse of A; and under what condition, a square matrix A has minimum condition number for its eigenproblem? Then we consider the second problem, i.e., optimum of K(A) = \\A\\ \\A(-1)\\(2) in error estimation.

关键词： matrix unitarily invariant norm condition number

ON THE VARIATIONS OF G_2

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2003年第3期24卷 387-394页

作者： LIU DONG LIN LEI department of mathematics, east china normal university, shanghai 200062, china. department of mathematics, east china normal university, shanghai 200062, china. department of mathematics East China Normal University Shanghai 200062 China

In [1], Shen Guangyu constructed several classes of new simple Lie algebras of characteristic 2, which are called the variations of G2. In this paper, the authors investigate their derivation algebras. It is shown that G2 and its variations all possess unique nondegenerate associative forms. The authors also find some nonsingular derivations of ViG for i = 3,4, 5, 6, and thereby construct some left-symmetric structures on Vi G for i = 3,4,5,6. Some errors about the variations of sl(3, F) in [1] are corrected.

关键词： Variation Derivation Associative form Left-symmetric structure

ON ABELIAN AUTOMORPHISM GROUPS OF SURFACES OF GENERAL TYPE

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 1996年第1期17卷 43-52页

作者： CAI JINXING(department of mathematics, east china normal university, shanghai 200062, china.) 华东师范大学数学系上海

It is proved that for a complex minimal smooth projective surface S of general type, its abelian automorphism group is of order≤36k2s+24, provided x(os)≥8, where Ks is the canonical divisor of S, and X(Os) the Euler... 详细信息

关键词： Projective surface Automorphism group Canonical divisor

ON THE APPROXIMATELY SIMILARITY OF OPERATORS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 1998年第4期19卷 465-472页

作者： WEI GUOQIANG (department of mathematics, east china normal university, shanghai 200062, china.) 华东师范大学数学系上海

The author shows that a rank-preserving *-isorporphism between separable C*-algebras with unity is approximately equivalent to the identity representation. Some applications are made for approximately similarity of n-... 详细信息

关键词： C*-algebra Rank-preserving *-isomorphism Approximately equevalent,Approximately similar n-tuples of operators

Orbits Heteroclinic to Invariant Manifolds

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 1996年第4期12卷 372-373,375-378页

作者： zhu Deming department of mathematics east china normal university shanghai, 200062 china department of mathematics East China Normal University Shanghai China

Using the theory of invariant manifolds, we give local expressions of the stable and unstable manifolds for normally hyperbolic invariant tori, and study the existence of transverse orbits heteroclinic to hyperbolic i... 详细信息

关键词： Invariant manifold Exponential dichotomy Heteroclinic orbit Transversality

Codimension 3 nonresonant bifurcations of homoclinic orbits with two inclination flips

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2005年第2期48卷 248-260页

作者： SHUI Shuliang & zhu Deming College of mathematics and Physics, Zhejiang normal university, Jinhua 321004, china department of mathematics, east china normal university, shanghai 200062, china College of mathematics and Physics Zhejiang Normal University Jinhua China department of mathematics East China Normal University Shanghai China

Homoclinic bifurcations in four-dimensional vector fields are investigated by setting up a local coordinate near a homoclinic orbit. This homoclinic orbit is principal but its stable and unstable foliations take inclination flip. The existence, nonexistence, and uniqueness of the 1-homoclinic orbit and 1-periodic orbit are studied. The existence of the two-fold 1-periodic orbit and three-fold 1 -periodic orbit are also obtained. It is indicated that the number of periodic orbits bifurcated from this kind of homoclinic orbits depends heavily on the strength of the inclination flip.

关键词： bifurcation, homoclinic orbit, non-resonance, inclination flip, 1-periodic orbit.

HOMOCLINIC BIFURCATION WITH CODIMENSION 3

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 1994年第2期15卷 205-216页

作者： zhu DEMING(department of Matehematics,east china normal university, shanghai 200062, china) 华东师范大学数学系上海 200062

First it is proved that both the integral of the divergence and the Melnikov function are invariants of the C2 transformation. Then, the problem of the planar homoclinic bifurcation with codimension 3 is considered. It is proved that, in a small neighborhood of the origin in the parameter space of a Cr (r≥5) system, there exist exactly two Cr-1 semi- stable- limit- cycle branching surfaces, and their common boundary is a unique Cr-1 three-multiple- limit-cycle branching curve. The bifurcation pictures and the asymptotic expansions of the bifurcation functions are given. The stability criterion for the homoclinic loop is also obtained when the integral of the divergence is zero. The proof of the auxiliary theorems will be presented in [16].

关键词： Homoclinic bifurcation Codimension Semi-stable-limit-cycle branch Three- multiple-limit- cycle branch.