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1.
In this article, we provide necessary and sufficient conditions for R = A ∝ E to be a valuation ring where E is a non-torsion or finitely generated A-module. Also, we investigate the (n, d) property of the valuation ring.  相似文献   

2.
    
N. Mahdou 《代数通讯》2013,41(11):3989-3995
ABSTRACT

In this article, we are mainly concerned with (n, d)-Krull rings, i.e., rings in which each n-presented prime ideal has height at most d. Precisely, we show that weakly n-Von Neumann regular rings are (n ? 1, 0)-Krull rings. Also, we prove that (n, d)-Krull property is not local property and that R is an (n, d)-Krull ring if and only if dim(R P ) ≤ d for each n-presented prime ideal P of R. Finally, we construct a class of (2, d)-Krull rings which are neither (2, d ? 1)-Krull rings (for d = 1) nor (1, d)-Krull rings for d = 0,1.  相似文献   

3.
Lixin Mao 《代数通讯》2013,41(7):2403-2418
Let R be a ring, and n and d fixed non-negative integers. An R-module M is called (n, d)-injective if Ext d+1 R (P, M) = 0 for any n-presented R-module P. M is said to be (n, d)-projective if Ext1 R (M, N) = 0 for any (n, d)-injective R-module N. We use these concepts to characterize n-coherent rings and (n, d)-rings. Some known results are extended.  相似文献   

4.
研究一类广义分数可扩图即分数(n,k,d)-图的性质.图G是分数(n,k,d)-图即删去G的任意n个顶点后的剩余子图G′含有k-对集,且G′的任意k-对集都可扩充成G′的分数亏格-d对集.得到了分数(n,k,d)-图分别添加边和顶点的一系列递推关系.  相似文献   

5.
《代数通讯》2013,41(10):3937-3953
Abstract

This paper investigates coherent-like conditions and related properties that a trivial extension R ? A ∝ E might inherit from the ring A for some classes of modules E. It captures previous results dealing primarily with coherence, and also establishes satisfactory analogues of well-known coherence-like results on pullback constructions. Our results generate new families of examples of rings (with zerodivisors) subject to a given coherent-like condition.  相似文献   

6.
7.
    
In this article, we verify Dade's projective invariant conjecture for the symplectic group Sp4(2 n ) and the special unitary group SU4(22n ) in the defining characteristic, that is, in characteristic 2. Furthermore, we show that the Isaacs–Malle–Navarro version of the McKay conjecture holds for Sp4(2 n ) and SU4(22n ) in the defining characteristic, that is, Sp4(2 n ) and SU4(22n ) are good for the prime 2 in the sense of Isaacs, Malle, and Navarro.  相似文献   

8.
一个(d,r;z]-disjunct矩阵在许多领域有着极为广泛的应用.利用n阶射影平面的性质构作了(d,r;z]-disjunct矩阵,并研究了它的检错性和纠错性.  相似文献   

9.
(d,r)-disjunct矩阵、(d,r,z)-disjunct矩阵、(d,r,z]-disjunct矩阵等是一类d-disjunct矩阵,它们比d-disjunct矩阵有着更为广泛的应用.介绍了这一类d-disjunct矩阵的一种简单构作方法,并计算了它的参数.  相似文献   

10.
    
In this work we investigate the transfer of the (n,d)-Krull property between domains arising from pullbacks. As an application, we construct a new class of non-coherent domains which are (0,d)-Krull domains, not (0,d ? 1)-Krull domains, and where the Krull dimension equals d + 1.  相似文献   

11.
    
Ahuva C. Shkop 《代数通讯》2013,41(10):3813-3823
In this article, I will prove that assuming Schanuel's conjecture, an exponential polynomial with algebraic coefficients can have only finitely many algebraic roots. Furthermore, this proof demonstrates that there are no unexpected algebraic roots of any such exponential polynomial. This implies a special case of Shapiro's conjecture: if p(x) and q(x) are two exponential polynomials with algebraic coefficients, each involving only one iteration of the exponential map, and they have common factors only of the form exp (g) for some exponential polynomial g, then p and q have only finitely many common zeros.  相似文献   

12.
令n是一个正整数,[n]={1,2,…,n}.利用集合[叫上的s-子集族((ns))构作了二元(p,r,d)-叠加码,研究了它的容错和析取性质并介绍了它在非适应性群测(Nonadaptive Group Testing)方面的应用.  相似文献   

13.
Abstract

In this paper we study the relationship between some homological properties such as the weak and the global dimension, the strong n-coherence, and the (n, d)-property, where n and d are two integers, of a commutative ring and its subrings retract. A special application is the transfer of these properties from a commutative ring to its fixed subring with respect to a subgroup of its group of automorphisms. It concludes with a discussion of the scopes and limits of our results.  相似文献   

14.
在有限射影平面上利用有限射影平面的性质构作了(ω,r,d)-CFF(N,T)系统,并利用有限射影平面的性质计算了它的参数.最后利用一个有限点集构作了一个(ω,r,d)-DS(N,T)系统并计算了它的参数.  相似文献   

15.
    
A graph with chromatic number k is called k-chromatic. Using computational methods, we show that the smallest triangle-free 6-chromatic graphs have at least 32 and at most 40 vertices. We also determine the complete set of all triangle-free 5-chromatic graphs up to 24 vertices. This implies that Reed's conjecture holds for triangle-free graphs up to at least this order. We also establish that a smallest regular triangle-free 5-chromatic graph has 24 vertices. Finally, we show that the smallest 5-chromatic graphs of girth at least 5 have at least 29 vertices and that the smallest 4-chromatic graphs of girth at least 6 have at least 25 vertices.  相似文献   

16.
    
The purpose of this article is to study a categorification of the n-th tensor power of the spin representation of U(𝔰𝔬(7, ?)) by using certain subcategories and projective functors of the Bernstein–Gelfand–Gelfand (BGG) category of the complex Lie algebra 𝔤𝔩 n .  相似文献   

17.
设n,a,b,c是正整数,gcd(a,b,c)=1,a,b≥3,且丢番图方程a~x+b~y=c~z只有正整数解(x,y,z)=(1,1,1).证明了若(x,y,z)是丢番图方程(an)~x+(bn)~y=(cn)~z的正整数解且(x,y,z)≠(1,1,1),则yzz或xzy.还证明了当(a,b,c)=(3,5,8),(5,8,13),(8,13,21),(13,21,34)时,丢番图方程(an)~x+(bn)~y=(cn)~z只有正整数解(x,y,z)=(1,1,1).  相似文献   

18.
    
E. Park 《代数通讯》2013,41(7):2184-2192
In this article, we construct examples of n-folds X carrying an ample line bundle A ∈ Pic X such that property N p fails for K X  + (n + 1 + p)A. This shows that the condition of Mukai's conjecture is optimal for every n ≥ 1 and p ≥ 0.  相似文献   

19.
    
Walid Al-Kawarit 《代数通讯》2013,41(10):3879-3896
In this article, we compare (n, m)-purities for different pairs of positive integers (n, m). When R is a commutative ring, these purities are not equivalent if R does not satisfy the following property: there exists a positive integer p such that, for each maximal ideal P, every finitely generated ideal of R P is p-generated. When this property holds, then the (n, m)-purity and the (n, m′)-purity are equivalent if m and m′ are integers ≥np. These results are obtained by a generalization of Warfield's methods. There are also some interesting results when R is a semiperfect strongly π-regular ring. We also compare (n, m)-flatnesses and (n, m)-injectivities for different pairs of positive integers (n, m). In particular, if R is right perfect and right self (?0, 1)-injective, then each (1, 1)-flat right R-module is projective. In several cases, for each positive integer p, all (n, p)-flatnesses are equivalent. But there are some examples where the (1, p)-flatness is not equivalent to the (1, p + 1)-flatness.  相似文献   

20.
利用辛空间上m维(m,s)型子空间的性质构作了(w,r,d)-CFF(N,T)系统,并利用子空间的计数定理计算了它的参数.一个(ω,r,d)-CFF(N,T)系统在许多领域有着极为广泛的应用.  相似文献   

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