环面代数扩张的同态

本文研究了环面代数(即C(T2))扩张问同态的性质．设E1和E2为环面代数通过K的本质酉扩张,φ,ψ:E1→E2为单同态,若φ,ψ在半群V(E1)及商代数上导出的映射一致,则φ与ψ是近似酉等价的．这里K为可分的无限维复Hilbert空间上的紧算子全体构成的C*-代数,V(E1)为E1的矩阵代数中投影的Murray-von Neumann等价类构成的交换半群．     

半环上Fuzzy k-理想的再定义

本文中，给出Fuzzy k－理想的新的概念作为半环上k－理想的新的模糊化概念，研究了半环同态下的Fuzzy k－理想的象及逆象的有关性质，并给出了非负整数半环N的Fuzzy k－理想的构造。     

一类无限维李代数的同构与单性

探讨了一类的无限维李代数,并构造了此类李代数的理想,同构,同态,并对其性质作了探讨.     

布尔代数的Fuzzy子代数和Fuzzy理想

引入了布尔代数的Fuzzy子代数、Fuzzy理想和Fuzzy商布尔代数的概念,给出了布尔代数的Fuzzy集是Fuzzy子代数(Fuzzy理想)的充要条件,讨论了布尔代数的Fuzzy子代数(Fuzzy理想)在布尔代数同态下的像和逆像,得到了布尔代数的Fuzzy子代数的同态基本定理。     

格的模糊软理想

将模糊软集与格的模糊理想概念相结合,引入了格的模糊软理想的概念,给出了它们的若干代数性质.定义了格的模糊软同态(同构)概念,证明了格的一个模糊软理想在模糊软同构(同态)下的像(原像)仍为模糊软理想的结论.     

关于弱不可约的Fuzzy理想

给出弱不可约的Fuzzy 理想的定义,研究Fuzzy 理想是弱不可约的Fuzzy 理想的充分和必要条件。另外,讨论了弱不可约的Fuzzy 理想的同态象与同态原象的代数性质。     

正规模糊格的素中理想

研究正规模糊格的素中理想与极大中理想的联系；并在一定的条件下证明了：正规模糊格的素中理想与模糊格同态之间存在一一对应关系。     

零维理想的一般准素分解

本文对零维理想关于某个变元是否为正常位置进行讨论,给出零维理想关于某个变元是否为正常位置的等价条件,得到一种较容易的求零维理想准素分解的方法,对某些理想能较快地得到部分准素分支,更有利于对理想进行准素分解.     

格的生成直觉模糊理想

首先探讨了由一个直觉模糊子集生成格的直觉模糊理想的问题,给出了生成直觉模糊理想的刻画;其次研究了在经典格同态意义下,直觉模糊理想的像以及逆像,得到了格同态与生成直觉模糊理想的关系.     

环中的粗素理想与模糊粗素理想

首次提出了环中的粗素理想与模糊粗素理想的概念，并讨论了它的性质及同态问题。     

Local Equations for the Toric Hilbert Scheme

We obtain local equations for the toric Hilbert scheme, which parametrizes all ideals with the same multigraded Hilbert function as a given toric ideal. We also prove a conjecture of Sturmfels' providing a criterion for an ideal to have such a Hilbert function.     

The Behaviors of Expansion Functor on Monomial Ideals and Toric Rings

In this article, we study some algebraic and combinatorial behaviors of expansion functor. We show that on monomial ideals some properties like polymatroidalness, weakly polymatroidalness, and having linear quotients are preserved under taking the expansion functor.

The main part of the article is devoted to study of toric ideals associated to the expansion of subsets of monomials which are minimal with respect to divisibility. It is shown that, for a given discrete polymatroid P, if toric ideal of P is generated by double swaps, then toric ideal of any expansion of P has such a property. This result, in a special case, says that White's conjecture is preserved under taking the expansion functor. Finally, the construction of Gröbner bases and some homological properties of toric ideals associated to expansions of subsets of monomials is investigated.     

Subdivisions of Toric Complexes

We introduce toric complexes as polyhedral complexes consisting of rational cones together with a set of integral generators for each cone, and we define their associated face rings. Abstract simplicial complexes and rational fans can be considered as toric complexes, and the face ring for toric complexes extends Stanley and Reisner’s face ring for abstract simplicial complexes [20] and Stanley’s face ring for rational fans [21]. Given a toric complex with defining ideal I for the face ring we give a geometrical interpretation of the initial ideals of I with respect to weight orders in terms of subdivisions of the toric complex generalizing a theorem of Sturmfels in [23]. We apply our results to study edgewise subdivisions of abstract simplicial complexes.     

Gr?bner bases of contraction ideals

We investigate Gr?bner bases of contraction ideals under monomial homomorphisms. As an application, we generalize the result of Aoki?CHibi?COhsugi?CTakemura and Ohsugi?CHibi for toric ideals of nested configurations.     

Laurent polynomials and Eulerian numbers

Duistermaat and van der Kallen show that there is no nontrivial complex Laurent polynomial all of whose powers have a zero constant term. Inspired by this, Sturmfels poses two questions: Do the constant terms of a generic Laurent polynomial form a regular sequence? If so, then what is the degree of the associated zero-dimensional ideal? In this note, we prove that the Eulerian numbers provide the answer to the second question. The proof involves reinterpreting the problem in terms of toric geometry.     

Ring graphs and complete intersection toric ideals

We study the family of graphs whose number of primitive cycles equals its cycle rank. It is shown that this family is precisely the family of ring graphs. Then we study the complete intersection property of toric ideals of bipartite graphs and oriented graphs. An interesting application is that complete intersection toric ideals of bipartite graphs correspond to ring graphs and that these ideals are minimally generated by Gröbner bases. We prove that any graph can be oriented such that its toric ideal is a complete intersection with a universal Gröbner basis determined by the cycles. It turns out that bipartite ring graphs are exactly the bipartite graphs that have complete intersection toric ideals for any orientation.     

On fuzzy irreducible ideals and homomorphisms

The algebraic nature of fuzzy irreducible ideals under homomorphisms is discussed.     

Rational points of lattice ideals on a toric variety and toric codes

We show that the number of rational points of a subgroup inside a toric variety over a finite field defined by a homogeneous lattice ideal can be computed via Smith normal form of the matrix whose columns constitute a basis of the lattice. This generalizes and yields a concise toric geometric proof of the same fact proven purely algebraically by Lopez and Villarreal for the case of a projective space and a standard homogeneous lattice ideal of dimension one. We also prove a Nullstellensatz type theorem over a finite field establishing a one to one correspondence between subgroups of the dense split torus and certain homogeneous lattice ideals. As application, we compute the main parameters of generalized toric codes on subgroups of the torus of Hirzebruch surfaces, generalizing the existing literature.     

Jordan homomorphisms of upper triangular matrix rings

In this paper we investigate Jordan homomorphisms of upper triangular matrix rings and give a sufficient condition under which they are necessarily homomorphisms or anti-homomorphisms.     

Semidefinite Characterization and Computation of Zero-Dimensional Real Radical Ideals

For an ideal I??[x] given by a set of generators, a new semidefinite characterization of its real radical I(V _?(I)) is presented, provided it is zero-dimensional (even if I is not). Moreover, we propose an algorithm using numerical linear algebra and semidefinite optimization techniques, to compute all (finitely many) points of the real variety V _?(I) as well as a set of generators of the real radical ideal. The latter is obtained in the form of a border or Gröbner basis. The algorithm is based on moment relaxations and, in contrast to other existing methods, it exploits the real algebraic nature of the problem right from the beginning and avoids the computation of complex components.