Algebra
http://www.hindawi.com
The latest articles from Hindawi Publishing Corporation
© 2014 , Hindawi Publishing Corporation . All rights reserved.

Unions of Parafree Lie Algebras
Wed, 13 Aug 2014 09:18:21 +0000
http://www.hindawi.com/journals/algebra/2014/385397/
We consider unions of parafree Lie algebras and we prove that such unions are again parafree under some conditions.
Naime Ekici and Zehra Velioğlu
Copyright © 2014 Naime Ekici and Zehra Velioğlu. All rights reserved.

A Study of Inverse Problems Based on Two Kinds of Special Matrix Equations in Euclidean Space
Mon, 26 May 2014 00:00:00 +0000
http://www.hindawi.com/journals/algebra/2014/392467/
Two special classes of symmetric coefficient matrices were defined based on characteristics matrix; meanwhile, the expressions of the solution to inverse problems are given and the conditions for the solvability of these problems are studied relying on researching. Finally, the optimal approximation solution of these problems is provided.
Rui Huang, Xiaodong Wu, Ruihe Wang, and Hui Li
Copyright © 2014 Rui Huang et al. All rights reserved.

Demazure Descent and Representations of Reductive Groups
Sun, 25 May 2014 10:58:34 +0000
http://www.hindawi.com/journals/algebra/2014/823467/
We introduce the notion of Demazure descent data on a triangulated category and define the descent category for such data. We illustrate the definition by our basic example. Let be a reductive algebraic group with a Borel subgroup . Demazure functors form Demazure descent data on and the descent category is equivalent to .
Sergey Arkhipov and Tina Kanstrup
Copyright © 2014 Sergey Arkhipov and Tina Kanstrup. All rights reserved.

On Determinantal Varieties of Hankel Matrices
Mon, 28 Apr 2014 08:00:28 +0000
http://www.hindawi.com/journals/algebra/2014/970157/
Let be a class of Hankel matrices whose entries, depending on a given matrix , are linear forms in variables with coefficients in a finite field . For every matrix in , it is shown that the varieties specified by the leading minors of orders from 1 to have the same number of points in . Further properties are derived, which show that sets of varieties, tied to a given Hankel matrix, resemble a set of hyperplanes as regards the number of points of their intersections.
Edoardo Ballico and Michele Elia
Copyright © 2014 Edoardo Ballico and Michele Elia. All rights reserved.

Simplices in the Endomorphism Semiring of a Finite Chain
Sun, 27 Apr 2014 08:50:15 +0000
http://www.hindawi.com/journals/algebra/2014/263605/
We establish new results concerning endomorphisms of a finite chain, if the cardinality of the image of such endomorphism is no more than some fixed number. The semiring of all such endomorphisms can be seen as a simplex whose vertices are the constant endomorphisms. We explore the properties of these simplices.
Ivan Trendafilov
Copyright © 2014 Ivan Trendafilov. All rights reserved.

On Integral Manifolds for Leibniz Algebras
Thu, 24 Apr 2014 08:37:41 +0000
http://www.hindawi.com/journals/algebra/2014/875981/
We discuss several partial solutions to the socalled “coquecigrue problem” of Loday; these solutions parallel, but also generalize in several directions, the classical Lie groupLie algebra correspondence. Our study highlights some clear similarities between the split and nonsplit cases and leads us to a general unifying scheme that provides an answer to the problem of the algebraic structure of a coquecigrue.
Juan Monterde and Fausto Ongay
Copyright © 2014 Juan Monterde and Fausto Ongay. All rights reserved.

A Construction of Bent Functions of Variables from a Bent Function of Variables and Its Cyclic Shifts
Thu, 17 Apr 2014 10:08:48 +0000
http://www.hindawi.com/journals/algebra/2014/701298/
We present a method to iteratively construct new bent functions of variables from a bent function of variables and its cyclic shift permutations using minterms of variables and minterms of 2 variables. In addition, we provide the number of bent functions of variables that we can obtain by applying the method here presented, and finally we compare this method with a previous one introduced by us in 2008 and with the Rothaus and MaioranaMcFarland constructions.
JoanJosep Climent, Francisco J. García, and Verónica Requena
Copyright © 2014 JoanJosep Climent et al. All rights reserved.

Vertex Coalgebras, Coassociator, and Cocommutator Formulas
Sun, 02 Mar 2014 13:26:01 +0000
http://www.hindawi.com/journals/algebra/2014/861768/
Based on the definition of vertex coalgebra introduced by Hubbard, 2009, we
prove that this notion can be reformulated using coskew symmetry, coassociator and
cocommutator formulas without restrictions on the grading. We also prove that a
vertex coalgebra can be defined in terms of dual versions of the axioms of Lie conformal
algebra and differential algebra.
Florencia Orosz Hunziker and José I. Liberati
Copyright © 2014 Florencia Orosz Hunziker and José I. Liberati. All rights reserved.

On Ordered QuasiGammaIdeals of Regular Ordered GammaSemigroups
Mon, 09 Dec 2013 16:00:41 +0000
http://www.hindawi.com/journals/algebra/2013/565848/
We introduce the notion of ordered quasiideals of regular ordered semigroups and study the basic properties of ordered quasiideals of ordered semigroups. We also characterize regular ordered semigroups in terms of their ordered quasiideals, ordered right ideals, and left ideals. Finally, we have shown that (i) a partially ordered semigroup is regular if and only if for every ordered biideal , every ordered ideal , and every ordered quasiideal , we have and (ii) a partially ordered semigroup is regular if and only if for every ordered quasiideal , every ordered left ideal , and every ordered rightideal , we have that .
M. Y. Abbasi and Abul Basar
Copyright © 2013 M. Y. Abbasi and Abul Basar. All rights reserved.

Commutative and Bounded BEalgebras
Thu, 05 Dec 2013 14:33:53 +0000
http://www.hindawi.com/journals/algebra/2013/473714/
We introduce the notions of the commutative and bounded BEAlgebras. We give some related properties of them.
Zekiye Çiloğlu and Yılmaz Çeven
Copyright © 2013 Zekiye Çiloğlu and Yılmaz Çeven. All rights reserved.

On the Jacobson Radical of an Semiring
Mon, 07 Oct 2013 14:15:37 +0000
http://www.hindawi.com/journals/algebra/2013/272104/
The notion of ary semimodules is introduced so that the Jacobson radical of an semiring is studied and some wellknown results concerning the Jacobson radical of a ring (a semiring or a ternary semiring) are generalized to an semiring.
Yongwen Zhu
Copyright © 2013 Yongwen Zhu. All rights reserved.

A Study on Fuzzy Ideals of Groups
Thu, 26 Sep 2013 11:15:48 +0000
http://www.hindawi.com/journals/algebra/2013/594636/
Using the idea of the new sort of fuzzy subnearring of a nearring, fuzzy subgroups, and their generalizations defined by various researchers, we try to introduce the notion of ()fuzzy ideals of groups. These fuzzy ideals are characterized by their level ideals, and some other related properties are investigated.
B. Davvaz and O. Ratnabala Devi
Copyright © 2013 B. Davvaz and O. Ratnabala Devi. All rights reserved.

Two Interacting Coordinate Hopf Algebras of Affine Groups of Formal Series on a Category
Thu, 19 Sep 2013 13:14:34 +0000
http://www.hindawi.com/journals/algebra/2013/370618/
A locally finite category is defined as a category in which every arrow admits only finitely many
different ways to be factorized by composable arrows. The large algebra of such categories over
some fields may be defined, and with it a group of invertible series (under multiplication). For
certain particular locally finite categories, a substitution operation, generalizing the usual substitution
of formal power series, may be defined, and with it a group of reversible series (invertible
under substitution). Moreover, both groups are actually affine groups. In this contribution, we
introduce their coordinate Hopf algebras which are both free as commutative algebras. The
semidirect product structure obtained from the action of reversible series on invertible series by
antiautomorphisms gives rise to an interaction at the level of their coordinate Hopf algebras
under the form of a smash coproduct.
Laurent Poinsot
Copyright © 2013 Laurent Poinsot. All rights reserved.

Construction and Composition of Rooted Trees via Descent Functions
Tue, 27 Aug 2013 16:06:44 +0000
http://www.hindawi.com/journals/algebra/2013/543913/
We propose a novel approach for studying rooted trees by using functions that we will call descent functions. We provide a construction method for rooted trees that allows to study their properties through the use of descent functions. Moreover, in this way, we are able to compose rooted trees with each other. Such a new composition of rooted trees is a very powerful tool applied in this paper in order to obtain important results as the creation of new rational and Pythagorean trees.
Marco Abrate, Stefano Barbero, Umberto Cerruti, and Nadir Murru
Copyright © 2013 Marco Abrate et al. All rights reserved.

Some Results on Strict Graded Categorical Groups
Mon, 26 Aug 2013 09:25:24 +0000
http://www.hindawi.com/journals/algebra/2013/306978/
We present some applications of strict graded categorical groups to the construction of the obstruction of an equivariant kernel and to the classification of equivariant group extensions which are central ones. The composition of a graded categorical group and an equivariant group homomorphism is also determined.
Nguyen Tien Quang and Che Thi Kim Phung
Copyright © 2013 Nguyen Tien Quang and Che Thi Kim Phung. All rights reserved.

A Characterization of Projective Special Unitary Group U3(7) by nse
Sat, 24 Aug 2013 08:07:54 +0000
http://www.hindawi.com/journals/algebra/2013/983186/
Let a group and be the set of element orders of . Let and let be the number of elements of order in . Let nse. In Khatami et al. and Liu's works, and are uniquely determined by nse. In this paper, we prove that if is a group such that nse = nse, then .
Shitian Liu
Copyright © 2013 Shitian Liu. All rights reserved.

On QuasiDense Submodules and Pure Envelopes of QTAG Modules
Mon, 29 Jul 2013 10:40:07 +0000
http://www.hindawi.com/journals/algebra/2013/873193/
A module over an associative ring with unity is a QTAG module if every finitely generated submodule of any homomorphic image of is a direct sum of uniserial modules. There are many fascinating properties of QTAG modules of which pure submodules and high submodules are significant. A submodule is quasidense in if is divisible, for every pure submodule of containing Here we study these submodules and obtain some interesting results. Motivated by neat envelope, we also define pure envelope of a submodule as the pure submodule if has no direct summand containing We find that pure envelopes of have isomorphic basic submodules, and if is the direct sum of uniserial modules, then all pure envelopes of are isomorphic.
Alveera Mehdi, Fahad Sikander, and Firdhousi Begum
Copyright © 2013 Alveera Mehdi et al. All rights reserved.

A Note on Hobby’s Theorem of Finite Groups
Sun, 07 Jul 2013 08:56:25 +0000
http://www.hindawi.com/journals/algebra/2013/135045/
It is well known that the Frattini subgroups of any finite groups are nilpotent. If a finite group is not nilpotent, it is not the Frattini subgroup of a finite group. In this paper, we mainly discuss what kind of finite nilpotent groups cannot be the Frattini subgroup of some finite groups and give some results. Moreover, we generalize Hobby’s Theorem.
Qingjun Kong
Copyright © 2013 Qingjun Kong. All rights reserved.

The Depth of Generalized Full Terms and Generalized Full Hypersubstitutions
Wed, 26 Jun 2013 15:17:15 +0000
http://www.hindawi.com/journals/algebra/2013/396464/
We generalize the concept of a full term which was introduced by Denecke and Changphas and the concept of the depth of a hypersubstitution which was introduced by Denecke et al. to the depth of a generalized full term and the depth of a generalized full hypersubstitution and then derive the formular for its depth.
Sarawut Phuapong and Sorasak Leeratanavalee
Copyright © 2013 Sarawut Phuapong and Sorasak Leeratanavalee. All rights reserved.

Bound on the Minimum Eigenvalue of Matrices Involving Hadamard Products
Wed, 19 Jun 2013 08:49:09 +0000
http://www.hindawi.com/journals/algebra/2013/102438/
We present a new lower bound on the minimum eigenvalue of matrices involving Hadamard products , and we show that our lower bound is larger than the lower bound . Three examples verify our result.
Kun Du, Guiding Gu, and Guo Liu
Copyright © 2013 Kun Du et al. All rights reserved.

Finite Groups with Some Supplemented Subgroups
Tue, 18 Jun 2013 14:23:16 +0000
http://www.hindawi.com/journals/algebra/2013/153691/
Let be a subgroup of a finite group , a prime dividing the order of , and a Sylow subgroup of for prime We say that is supplemented in if there is a subgroup of such that and where denotes the subgroup of generated by all those subgroups of which are quasinormally embedded in In this paper, we characterize nilpotency and supersolvability of under the assumption that all maximal subgroups of are supplemented in .
Guo Zhong, Liying Yang, Huaquan Wei, Xuanlong Ma, and Jiayi Xia
Copyright © 2013 Guo Zhong et al. All rights reserved.

On Cogenerated Commutative Unital Algebras
Wed, 05 Jun 2013 13:38:42 +0000
http://www.hindawi.com/journals/algebra/2013/452862/
GelfandNaimark's theorem states that every commutative algebra is isomorphic to a complex valued algebra of continuous functions over a suitable compact space. We observe that for a completely regular space , is denseseparable if and only if is cogenerated if and only if every family of maximal ideals of with zero intersection has a subfamily with cardinal number less than and zero intersection. This gives a simple characterization of cogenerated commutative unital algebras via their maximal ideals.
Ehsan Momtahan
Copyright © 2013 Ehsan Momtahan. All rights reserved.

Wronskian Envelope of a Lie Algebra
Wed, 29 May 2013 10:56:18 +0000
http://www.hindawi.com/journals/algebra/2013/341631/
The famous PoincaréBirkhoffWitt theorem states that a Lie algebra, free as a module, embeds
into its associative envelope—its universal enveloping algebra—as a subLie algebra for the usual commutator Lie bracket. However, there is another functorial way—less known—to associate a Lie algebra to an associative algebra and inversely. Any commutative algebra equipped with a derivation , that is, a commutative differential algebra, admits a Wronskian bracket under which it becomes a Lie algebra. Conversely, to any Lie algebra a commutative differential algebra is universally associated, its Wronskian envelope, in a way similar to the associative envelope. This contribution is the beginning of an investigation of these relations between Lie algebras and differential algebras which is parallel to the classical theory. In particular, we give a sufficient condition under which a Lie algebra may be embedded into its Wronskian envelope, and we present the construction of the free Lie algebra with this property.
Laurent Poinsot
Copyright © 2013 Laurent Poinsot. All rights reserved.

Recent Progress on Submersions: A Survey and New Properties
Sun, 12 May 2013 13:54:14 +0000
http://www.hindawi.com/journals/algebra/2013/128064/
This paper is a survey about recent progress on submersive morphisms of schemes combined with new results that we prove. They concern the class of quasicompact universally subtrusive morphisms that we introduced about 30 years ago. They are revisited in a recent paper by Rydh, with substantial complements and key results. We use them to show ArtinTatelike results about the 14th problem of Hilbert, for a base scheme either Noetherian or the spectrum of a valuation domain. We look at faithfully flat morphisms and get “almost” ArtinTatelike results by considering the Goldman (finite type) points of a scheme. Bjorn Poonen recently proved that universally closed morphisms are quasicompact. By introducing incomparable morphisms of schemes, we are able to characterize universally closed surjective morphisms that are either integral or finite. Next we consider pure morphisms of schemes introduced by Mesablishvili. In the quasicompact case, they are universally schematically dominant morphisms. This leads us to a characterization of universally subtrusive morphisms by purity. Some results on the schematically dominant property are given. The paper ends with properties of monomorphisms and topological immersions, a dual notion of submersions.
Gabriel Picavet
Copyright © 2013 Gabriel Picavet. All rights reserved.

The Cyclic Graph of a Finite Group
Tue, 16 Apr 2013 08:14:47 +0000
http://www.hindawi.com/journals/algebra/2013/107265/
The cyclic graph of a finite group is
as follows: take as the vertices of and join two distinct
vertices and if is cyclic. In this paper, we
investigate how the graph theoretical properties of affect the group theoretical
properties of . First, we consider some properties of
and characterize certain finite groups whose cyclic graphs have some properties.
Then, we present some properties of the cyclic graphs of
the dihedral groups and the generalized quaternion groups for some .
Finally, we present some parameters about the cyclic graphs of finite noncyclic groups of
order up to .
Xuan Long Ma, Hua Quan Wei, and Guo Zhong
Copyright © 2013 Xuan Long Ma et al. All rights reserved.

Applications of Soft Sets in BEAlgebras
Wed, 10 Apr 2013 09:59:33 +0000
http://www.hindawi.com/journals/algebra/2013/368962/
The notion of intersectional soft subalgebras of a BEalgebra is introduced, and related properties are investigated. Characterization of an intersectional soft subalgebra is discussed. The problem of classifying intersectional soft subalgebras by their inclusive subalgebras will be solved.
Young Bae Jun and Sun Shin Ahn
Copyright © 2013 Young Bae Jun and Sun Shin Ahn. All rights reserved.

A Morphism Double Category and Monoidal Structure
Mon, 25 Mar 2013 10:17:40 +0000
http://www.hindawi.com/journals/algebra/2013/460582/
We provide a recipe for “fattening” a category that leads to the construction of a double category. Motivated by an example where the underlying category has vector spaces as objects, we show how a monoidal category leads to a law of composition, satisfying certain coherence properties, on the object set of the fattened category.
Saikat Chatterjee, Amitabha Lahiri, and Ambar N. Sengupta
Copyright © 2013 Saikat Chatterjee et al. All rights reserved.

Real and Complex Rank for Real Symmetric Tensors with Low Ranks
Thu, 21 Mar 2013 14:37:38 +0000
http://www.hindawi.com/journals/algebra/2013/794054/
We study the case of a real homogeneous polynomial whose minimal real and complex decompositions in terms of powers of linear forms are different. We prove that if the sum of the complex and the real ranks of is at most , then the difference of the two decompositions is completely determined either on a line or on a conic or two disjoint lines.
Edoardo Ballico and Alessandra Bernardi
Copyright © 2013 Edoardo Ballico and Alessandra Bernardi. All rights reserved.

Assembling Crystals of Type A
Wed, 20 Mar 2013 14:28:34 +0000
http://www.hindawi.com/journals/algebra/2013/483949/
Regular crystals are certain edgecolored directed graphs, which are related to representations of the quantized universal enveloping algebra . For such a crystal with colors , we consider its maximal connected subcrystals with colors and with colors and characterize the interlacing structure for all pairs of these subcrystals. This enables us to give a recursive description of the combinatorial structure of via subcrystals and develop an efficient procedure of assembling .
Vladimir I. Danilov, Alexander V. Karzanov, and Gleb A. Koshevoy
Copyright © 2013 Vladimir I. Danilov et al. All rights reserved.

The Generalization of Prime Modules
Wed, 20 Mar 2013 09:23:30 +0000
http://www.hindawi.com/journals/algebra/2013/581023/
Piecewise prime (PWP) module
is defined in terms of a set of triangulating idempotents in . The class of PWP modules properly contains the class of prime modules. Some properties of these modules are investigated here.
M. Gurabi
Copyright © 2013 M. Gurabi. All rights reserved.