Invariants of Lagrangians on Weil Bundles and Their Classifications

Let Q:BA be an algebra epimorphism, where A, B are Weil algebras. Let Q M:T B M T AM denote the canonical extension of Q, from the bundle of B-velocities onto the bundle of A-velocities, over a manifold M. Classifications of all natural operators transforming real-valued functions on T AM into real-valued functions on T BM or into 1-forms on T BM of finite order with respect to Q M are given, provided the dimension of M is sufficiently large.     

Alexandroff's Double Arrow Compact Space and Approximation Theory

A compact space Q similar to the compact space known as Alexandroff's double arrow space is constructed. It is shown that the real space C(Q) has no Chebyshev subspaces of codimension >1, but the complex space C(Q) has such subspaces.     

An Example of a Positive Semidefinite Double Sequence Which is Not a Moment Sequence

The first explicit example of a positive semidefinite double sequence which is not a moment sequence was given by Friedrich. We present an example with a simpler definition and more moderate growth as (m, n) .     

Invariant Lagrangians and a new method of integration of nonlinear equations

A method for solving the inverse variational problem for differential equations admitting a Lie group is presented. The method is used for determining invariant Lagrangians and integration of second-order nonlinear differential equations admitting two-dimensional noncommutative Lie algebras. The method of integration suggested here is quite different from Lie's classical method of integration of second-order ordinary differential equations based on canonical forms of two-dimensional Lie algebras. The new method reveals existence and significance of one-parameter families of singular solutions to nonlinear equations of second order.     

使用对称性计算一类有限元基函数的二重积分

本文使用对称性计算一类有限元基函数在非规则区域的二重积分.通过两个算例验证对称性技巧在重积分计算上所带来的极大便利性.本文的内容进一步说明了使用对称性进行重积分计算在其他学科的应用价值.     

Nontrivial Critical Networks. Singularities of Lagrangians and a Criterion for Criticality

We single out the class of so-called quasiregular Lagrangians, which have singularities on the zero section of the cotangent bundle to the manifold on which extremal networks are considered. A criterion for a network to be extremal is proved for such Lagrangians: the Euler--Lagrange equations must be satisfied on each edge, and some matching conditions must be valid at the vertices.     

中心对称三次系统的一类双纽线有界周期环域的poincare分支

证明中心对称三次系统的一类双纽线有界周期环域的 poincare分支至少可以出现作对称 (3,3)分布的六个极限环 .     

Quasiconvex functions and null Lagrangians in the stability problems of classes of mappings

We obtain stability theorems for classes of solutions to the differential equations constructed by means of quasiconvex functions and null Lagrangians.     

L 2-Topology and Lagrangians in the Space of Connections Over a Riemann Surface

We examine the L ²-topology of the gauge orbits over a closed Riemann surface. We prove a subtle local slice theorem based on the div-curl lemma of harmonic analysis, and deduce local pathwise connectedness of the gauge orbits. Based on a quantitative version of the connectivity, we generalize compactness results for anti-self-dual instantons with Lagrangian boundary conditions to general gauge-invariant Lagrangian submanifolds. This provides the foundation for the construction of instanton Floer homology for pairs of a 3-manifold with boundary and a Lagrangian in the configuration space over the boundary.     

图的倍图与补倍图

计算机科学数据库的关系中遇到了可归为倍图或补倍图的参数和哈密顿圈的问题．对简单图C,如果V（D（G））：V（G）∪V（G′）E（D（G））=E（C）∪E（C″）U{vivj′｜vi∈V（G）,Vj′∈V（G′）且vivj∈E（G））那么,称D（C）是C的倍图,如果V（D（G））=V（C）∪V（G′）,E（D（C））：E（C）∪E（G′）∪{vivj′}vi∈V（G）,vj′∈V（G’）and vivj∈（G））,称D（C）是G的补倍图,这里G′是G的拷贝．本文研究了D（G）和D的色数,边色数,欧拉性,哈密顿性和提出了D（G） 的边色数是D（G）的最大度等公开问题．     

Geometrical Interpretation of General Complex Algebra and its Application in Relativistic Mechanics

In a generalized formulation of the relativistic dynamics with internal conformation an important role is played by a quadratic polynomial, the coefficients and eigenvalues of which are generated by outer and inner momenta of the relativistic particle. This polynomial induces the general complex algebra, GC. In this paper we explore the geometrical and physical aspects of the evolution generated by the algebraic operations of the GC-algebra. It is shown that the geometrical image of the GC-number is given by a straight line passing through two given points in an euclidean plane. In this representation the straight line is characterized by a norm and an argument. The motions of the straight line are described by hyperbolic trigonometry which brings a correspondence between the Euclidean geometry and the hyperbolic one. It is proved that the evolution equation governed by the generator of the GC-algebra describes the energy conservation law of the relativistic particle. This evolution is depicted on the Euclidean plane as a rotational motion of the straight line, tangent to the circle with radius equal to the mass of the particle. In this way we come to new representation for the momenta in relativistic dynamics.     

BRST-Invariant Algebra of Constraints in Terms of Commutators and Quantum Antibrackets

We establish the general structure of the BRST-invariant algebra of constraints in its commutator and antibracket forms via the formulation of algebra-generating equations in a supplementally extended phase space. New ghost-type variables behave as fields and antifields with respect to quantum antibrackets. The explicit form of the BRST-invariant gauge algebra is given in detail for rank-one theories with a Weyl- and a Wick-ordered ghost sector. We construct a fixed-gauge unitarizing Hamiltonian and show that the formalism is physically equivalent to the standard BRST–BFV approach.     

<Emphasis Type="Italic">β</Emphasis>-character Algebra and a Commuting Pair in Hopf Algebras

Let K be a field. Let H be a finite-dimensional semisimple and cosemisimple K-Hopf algebra. In this paper, we introduce a notion of β-character algebra C _β (H) for each group-like element β in H ^∗. We prove that Radford’s action of the Drinfel’d double D(H) on H _β (see Radford, J. Algebra, 270:670–695, 2003) and the right hit action of the β-character algebra C _β (H) on H _β form a commuting pair. This generalizes an earlier result of Zhu (Proc. Amer. Math. Soc., 125(10):2847–2851, 1997). A K-basis of C _β (H) is given when H is split semisimple. Finally, as an example, we explicitly construct all the simple modules for the Drinfel’d double of the unique 8-dimensional non-commutative and non-cocommutative semisimple Hopf algebra. Presented by S. Montgomery.     

例谈数形结合在高数解题中的应用

通过微分中值的等式证明、求渐近线方程、定积分中的换元法、几何图形的描绘以及曲线积分的计算等例题,说明将代数运算或证明与几何直观相结合给解高等数学问题带来的好处．     

Hodge Numbers of a Hypothetical Complex Structure on the Six Sphere

We prove that the terms E_r^p,q(S⁶) in the Frölicher spectral sequence associated to any hypothetical complex structure on S⁶ would satisfy Serre duality. It is also shown that the vanishing of the Dolbeault cohomology group H^1,1(S⁶) ensures the existence of a holomorphic 2-form on S⁶ living even in E₂^2,0(S⁶), which in particular implies the nondegeneration of Frölicher's sequence at the second level.     

Cyclic comodules, the homology of j, and j-homology

We provide a somewhat simpler computation of the homology of the image of j spectrum using general techniques for comodules over a coalgebra. We also compute the homotopy of the spectrum HFpj_∧HFp, the spectrum which plays the role of HFp∧HFp in the category of j-modules.     

Properties of the Distance Function to Strongly and Weakly Convex Sets in a Nonsymmetrical Space

We consider the distance function (DF), given by the caliber (the Minkowski gauge function) of a convex body, from a point to strictly, strongly, and weakly convex sets in an arbitrary Hilbert space. Some properties of the caliber of a strongly convex set and the conditions for obtaining a strict, strong, or weak convexity of Lebesgue sets for the distance function are established in accordance with the requirements for the set, the caliber of which specifies the distance function, and the set to which the distance is measured. The corresponding inequalities are obtained that reflect the behavior of the distance function on segments and allow comparing it with strictly, strongly, or weakly convex functions.     

Galois Theory and a New Homotopy Double Groupoid of a Map of Spaces

The authors have used generalised Galois Theory to construct a homotopy double groupoid of a surjective fibration of Kan simplicial sets. Here we apply this to construct a new homotopy double groupoid of a map of spaces, which includes constructions by others of a 2-groupoid, cat¹-group or crossed module. An advantage of our construction is that the double groupoid can give an algebraic model of a foliated bundle.     

Ext groups in the category of bimodules over a simple Leibniz algebra

In this article, we generalize Loday and Pirashvili's [11] computation of the Ext-category of Leibniz bimodules for a simple Lie algebra to the case of a simple (non Lie) Leibniz algebra. Most of the arguments generalize easily, while the main new ingredient is the Feldvoss-Wagemann's cohomology vanishing theorem for semi-simple Leibniz algebras.