Compression bounds for Lipschitz maps from the Heisenberg group to <Emphasis Type="Italic">L</Emphasis><Subscript>1</Subscript>

We prove a quantitative bi-Lipschitz non-embedding theorem for the Heisenberg group with its Carnot–Carathéodory metric and apply it to give a lower bound on the integrality gap of the Goemans–Linial semidefinite relaxation of the sparsest cut problem.     

Nöther-type theorem of piecewise algebraic curves on quasi-cross-cut partition

Nöther’s theorem of algebraic curves plays an important role in classical algebraic geometry. As the zero set of a bivariate spline, the piecewise algebraic curve is a generalization of the classical algebraic curve. Nöther-type theorem of piecewise algebraic curves is very important to construct the Lagrange interpolation sets for bivariate spline spaces. In this paper, using the characteristics of quasi-cross-cut partition, properties of bivariate splines and results in algebraic geometry, the Nöther-type theorem of piecewise algebraic curves on the quasi-cross-cut is presented.     

The colorful Helly theorem and colorful resolutions of ideals

We demonstrate that the topological Helly theorem and the algebraic Auslander-Buchsbaum theorem may be viewed as different versions of the same phenomenon. Using this correspondence we show how the colorful Helly theorem of I. Barany and its generalizations by G. Kalai and R. Meshulam translate to the algebraic side. Our main results are algebraic generalizations of these translations, which in particular give a syzygetic version of Helly’s theorem.     

Nöther-type theorem of piecewise algebraic curves on triangulation

The piecewise algebraic curve is a kind generalization of the classical algebraic curve. Nöther-type theorem of piecewise algebraic curves on the cross-cut partition is very important to construct the Lagrange interpolation sets for a bivariate spline space. In this paper, using the properties of bivariate splines, the Nöther-type theorem of piecewise algebraic curves on the arbitrary triangulation is presented.     

嵌入定理与代数数域上的大筛法

<正> 本文把数理方程研究中常用的嵌入定理稍作推广,应用到代数数域上来,并把[4]中第四章的定理4.2和[1,5]中的均值定理推广到代数数域上. 为此,先介绍一些符号与约定,基本上采自[2]. 设K为-n次代数数域,按通常的记号,记作n=r_1+2r_2.以Z_k表K中的整数环. 1.设为一理想,如α,β∈Z_k,|(α-β),则记α≡β(mod ).按此可把K中的整数分类,其类数为N.Z_k中与互素的整数在上述分类中占住类数为     

A generalization of Dirichlet's unit theorem

In this paper, we obtain a unit theorem for algebraic tori defined over an algebraic number field, which generalizes Dirichlet's unit theorem as well as the S-unit theorem due to Hasse and Chevalley.     

N(o)ther-type theorem of piecewise algebraic curves on triangulation

The piecewise algebraic curve is a kind generalization of the classical algebraic curve.N(o)ther-type theorem of piecewise algebraic curves on the cross-cut partition is very important to construct the Lagrange interpolation sets for a bivariate spline space. In this paper, using the properties of bivariate splines, the N(o)ther-type theorem of piecewise algebraic curves on the arbitrary triangulation is presented.     

On solving equations of algebraic sum of equal powers

It is well known that a system of equations of sum of equal powers can be converted to an algebraic equation of higher degree via Newton's identities. This is the Viete-Newton theorem. This work reports the generalizations of the Viete-Newton theorem to a system of equations of algebraic sum of equal powers. By exploiting some facts from algebra and combinatorics, it is shown that a system of equations of algebraic sum of equal powers can be converted in a closed form to two algebraic equations, whose degree sum equals the number of unknowns of the system of equations of algebraic sum of equal powers.     

Notes on a theorem of Naji

We present a new proof of an algebraic characterization of circle graphs due to W. Naji.For bipartite graphs, Naji’s theorem is equivalent to an algebraic characterization of planar matroids due to J. Geelen and B. Gerards. Naji’s theorem also yields an algebraic characterization of permutation graphs.     

量词模态逻辑的代数语义学（Ⅲ）──关于不含Barcan公式的正规模态系统的情形

本文首先讨论嵌套论域语义的相应代数语义并由Ｈｕｇｈｅｓ和Ｃｒｅｓｓｗｅｌｌ在［５］中建立的关于具有嵌套论域的正规量词模态系统的关系语义完全性定理推出其相应的代数语义完全性定理：然后对于具有任意可变论域语义的正规系统，我们用Ｈｅｎｋｉｎ方法给出其关于狭义Ｋｒｉｐｋｅ语义的关系语义完全性定理，由此通过将关系语义转化为代数语义从而亦推得其代数语义完全性定理。     

An algebraic index theorem for orbifolds

Using the concept of a twisted trace density on a cyclic groupoid, a trace is constructed on a formal deformation quantization of a symplectic orbifold. An algebraic index theorem for orbifolds follows as a consequence of a local Riemann-Roch theorem for such densities. In the case of a reduced orbifold, this proves a conjecture by Fedosov, Schulze, and Tarkhanov. Finally, it is shown how the Kawasaki index theorem for elliptic operators on orbifolds follows from this algebraic index theorem.     

On the curvature of algebraic hypersurfaces

Using algebraic residue theory, we try to generalize a theorem of Chasles about osculating circles of plane algebraic curves to algebraic hypersurfaces over algebraically closed fields of characteristic zero.     

Algebraic Functions,Calculus Style

We investigate the structure and properties of the explicit algebraic functions described in calculus texts and their relation to algebraic functions. A structure theorem enables us to construct a large number of examples. An example of an algebraic function that is not explicitly algebraic is studied, and an abstract algebraic context is provided for the theory.     

On the converse of Abel's theorem in characteristic p

Darboux's and Griffiths' converse of Abel's theorem says (in effect) that any addition law like those obtained via Abel's theorem from sums of Abelian integrals on algebraic curves must in fact arise from this sort of algebraic situation. In this paper, we prove a characteristic p version of the result for plane cubic curves.     

On some combinatorial properties of algebraic matroids

It was proved implicitly by Ingleton and Main and explicitly by Lindström that if three lines in the algebraic matroid consisting of all elements of an algebraically closed field are not coplanar, but any two of them are, then they pass through one point. This theorem is extended to a more general result about the intersection of subspaces in full algebraic matroids. This result is used to show that the minimax theorem for matroid matching, proved for linear matroids by Lovász, remains valid for algebraic matroids.     

FREE SOLVABLE P-ALGEBRAS

The construction of a free solvable P-algebra of finite degree k in the variety of all solvable P-algebras of degree at most k (k ≥ 1) has been given. Some properties of the same have been studied. The structure of the free solvable P-algebra has been viewed as a module over a ring with several objects. The Magnus embedding theorem associated with the Fox-derivative in a free group ring has been considered to prove properties associated with the partial (Fox) derivative in a free associative ring. Residual nilpotency and triviality of the center of a free metabelian P-algebra has been proved. Various properties of a homomorphism associated with a free metabelian P-algebra of finite rank have been studied. The non-embedding property of a free solvable P-algebra of degree k of higher rank in a lower rank has also been presented here.     

Die algebraischen Konoide mit ebener Striktionslinie

Among the algebraic ruled surfaces a theorem ofH. Brauner characterizes certain helicoids of projective screw motions by the property to possess continuous sets of plane shadow curves. Making use of this theorem all algebraic conoids with a plane striction curve are determined in euclidean 3-space and some properties of these curves are discussed.     

An algebraic certificate for Budan’s theorem

The existing algorithms to construct the real closure of an ordered field involve very high complexities. These algorithms are based on Sturm’s theorem which we suspect to be one reason for the complexities since all known proofs of Sturm’s theorem use Rolle’s theorem which is problematic in a constructive context.Therefore we propose to replace the use of Sturm’s theorem by Budan’s theorem. In this paper we present as a first step in this direction an algebraic certificate for Budan’s theorem. An algebraic certificate is a certain kind of proof of a statement. In particular, it is an algorithm which produces, from an arbitrary data in the premise of the statement, explicit (in)equalities which express the conclusion.     

射影空间中代数曲线与超曲面的一些新的性质

发现了代数曲线的新的不变量一特征数,并得到了Pascal定理的不同于3次曲线的Cllasles定理和高次曲线中的Cayley-Bacharach定理等形式的高次推广.进一步研究了平面代数曲线的一些性质.通过定义m次Pascal超曲面,将Pascal定理推广到n维射影空间的m次超曲面中,证明了n-单纯形上的Pascal点位于一个m次Pascal超曲面的充要条件是其每个2维面上的Pascal点分别位于m次平面Pascal空间的一条代数曲线上.进一步,给出了一定条件下m次Pascal超曲面与m-1次Pascal超曲面之间的内在关系.     

On matrix analogs of Fermat’s little theorem

The theorem proved in this paper gives a congruence for the traces of powers of an algebraic integer for the case in which the exponent of the power is a prime power. The theorem implies a congruence in Gauss’ form for the traces of the sums of powers of algebraic integers, generalizing many familiar versions of Fermat’s little theorem. Applied to the traces of integer matrices, this gives a proof of Arnold’s conjecture about the congruence of the traces of powers of such matrices for the case in which the exponent of the power is a prime power.