Algebraic and combinatorial properties of ideals and algebras of uniform clutters of TDI systems

نویسندگان

  • Luis A. Dupont
  • Rafael H. Villarreal
چکیده

Let C be a uniform clutter and let A be the incidence matrix of C. We denote the column vectors of A by v1, . . . , vq . Under certain conditions we prove that C is vertex critical. If C satisfies the max-flow min-cut property, we prove that A diagonalizes over Z to an identity matrix and that v1, . . . , vq form a Hilbert basis. We also prove that if C has a perfect matching such that C has the packing property and its vertex covering number is equal to 2, then A diagonalizes over Z to an identity matrix. If A is a balanced matrix we prove that any regular triangulation of the cone generated by v1, . . . , vq is unimodular. Some examples are presented to show that our results only hold for uniform clutters. These results are closely related to certain algebraic properties, such as the normality or torsion-freeness, of blowup algebras of edge ideals and to finitely generated abelian groups. They are also related to the theory of Gröbner bases of toric ideals and to Ehrhart rings.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

FUZZY OBSTINATE IDEALS IN MV-ALGEBRAS

In this paper, we introduce the notion of fuzzy obstinate ideals in MV -algebras. Some properties of fuzzy obstinateideals are given. Not only we give some characterizations of fuzzy obstinate ideals, but also bring the extension theorem of fuzzy obstinate ideal of an MV -algebra A. We investigate the relationships between fuzzy obstinate ideals and the other fuzzy ideals of an MV -algebra. We ...

متن کامل

Blowup algebras of square-free monomial ideals and some links to combinatorial optimization problems

Let I = (x1 , . . . , xq ) be a square-free monomial ideal of a polynomial ring K[x1, . . . , xn] over an arbitrary field K and let A be the incidence matrix with column vectors v1, . . . , vq. We will establish some connections between algebraic properties of certain graded algebras associated to I and combinatorial optimization properties of certain polyhedrons and clutters associated to A an...

متن کامل

APPROXIMATE IDENTITY IN CLOSED CODIMENSION ONE IDEALS OF SEMIGROUP ALGEBRAS

Let S be a locally compact topological foundation semigroup with identity and Ma(S) be its semigroup algebra. In this paper, we give necessary and sufficient conditions to have abounded approximate identity in closed codimension one ideals of the semigroup algebra $M_a(S)$ of a locally compact topological foundationsemigroup with identity.

متن کامل

A new branch of the logical algebra: UP-algebras

In this paper, we introduce a new algebraic structure, called a UP-algebra (UP means the University of Phayao) and a concept of UP-ideals, UP-subalgebras, congruences and UP-homomorphisms in UP-algebras, and investigated some related properties of them. We also describe connections between UP-ideals, UP-subalgebras, congruences and UP-homomorphisms, and show that the notion of UP-algebras is a ...

متن کامل

Derivations of UP-algebras by means of UP-endomorphisms

The notion of $f$-derivations of UP-algebras is introduced, some useful examples are discussed, and related properties are investigated. Moreover, we show that the fixed set and the kernel of $f$-derivations are UP-subalgebras of UP-algebras,and also give examples to show that the two sets are not UP-ideals of UP-algebras in general.

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • J. Comb. Optim.

دوره 21  شماره 

صفحات  -

تاریخ انتشار 2011