(بولتن انجمن ریاضی ایران) Bulletin of Iranian Mathematical Society(بولتن انجمن ریاضی ایران) Bulletin of Iranian Mathematical Society
http://iranjournals.nlai.ir/1174/
Sat, 29 Feb 2020 07:12:27 +0100FeedCreator(بولتن انجمن ریاضی ایران) Bulletin of Iranian Mathematical Society
http://iranjournals.nlai.ir/1174/
Feed provided by (بولتن انجمن ریاضی ایران) Bulletin of Iranian Mathematical Society. Click to visit.Benson's algorithm for nonconvex multiobjective problems via nonsmooth Wolfe duality
http://iranjournals.nlai.ir/1174/article_315333_43645.html
In this paper, we propose an algorithm to obtain an approximation set of the (weakly) nondominated points of nonsmooth multiobjective optimization problems with equality and inequality constraints. We use an extension of the Wolfe duality to construct the separating hyperplane in Benson's outer algorithm for multiobjective programming problems with subdifferentiable functions. We also formulate an infinitive approximation set of the (weakly) nondominated points of biobjective optimization problems. Moreover, we provide some numerical examples to illustrate the advantage of our algorithm.Mon, 30 Oct 2017 20:30:00 +0100Critical fixed point theorems in Banach algebras under weak topology features
http://iranjournals.nlai.ir/1174/article_315334_43645.html
In this paper, we establish some new critical fixed point theorems for the sum $AB+C$ in a Banach algebra relative to the weak topology, where $frac{I-C}{A}$ allows to be noninvertible. In addition, a special class of Banach algebras will be considered.Sat, 30 Sep 2017 20:30:00 +0100On annihilator ideals in skew polynomial rings
http://iranjournals.nlai.ir/1174/article_315335_43645.html
This article examines annihilators in the skew polynomial ring $R[x;alpha,delta]$. A ring is strongly right $AB$ if everynon-zero right annihilator is bounded. In this paper, we introduce and investigate a particular class of McCoy rings which satisfy Property ($A$) and the conditions asked by P.P. Nielsen. We assume that $R$ is an ($alpha$,$delta$)-compatible ring, and prove that, if $R$ is nil-reversible then the skew polynomial ring $R[x;alpha,delta]$is strongly right $AB$. It is also shown that, every right duo ring with an automorphism $alpha$ is skew McCoy. Moreover, if $R$ is strongly right $AB$ and skew McCoy, then $R[x;alpha]$ and $R[x;delta]$ have right Property ($A$).Sat, 30 Sep 2017 20:30:00 +0100The norm of pre-Schwarzian derivatives on bi-univalent functions of order $alpha$
http://iranjournals.nlai.ir/1174/article_315336_43645.html
In the present investigation, we give the best estimates for the norm of the pre-Schwarzian derivative $ T_{f}(z)=dfrac{f^{''}(z)}{f^{'}(z)} $ for bi-starlike functions and a new subclass of bi-univalent functions of order $ alpha $, where $Vert T_{f} Vert= sup_{|z|1} (1-|z|^{2})|dfrac{f^{''}(z)}{f^{'}(z)}|$.Sat, 30 Sep 2017 20:30:00 +0100Order-type existence theorem for second order nonlocal problems at resonance
http://iranjournals.nlai.ir/1174/article_315337_43645.html
This paper gives an abstract order-type existence theorem for second order nonlocal boundary value problems at resonance and obtain existence criteria for at least two positive solutions, where $f$ is a continuous function. Our results generalize or extend related results in the literature and give a positive answer to the question raised in the literature. An example is given to illustrate the new results.Mon, 30 Oct 2017 20:30:00 +0100Existence and blow-up of solution of Cauchy problem for the sixth order damped Boussinesq equation
http://iranjournals.nlai.ir/1174/article_315338_43645.html
In this paper, we consider the existence and uniqueness of the global solution for the sixth-order damped Boussinesq equation. Moreover, the finite-time blow-up of the solution for the equation is investigated by the concavity method.Sat, 30 Sep 2017 20:30:00 +0100Diagonal arguments and fixed points
http://iranjournals.nlai.ir/1174/article_315339_43645.html
A universal schema for diagonalization was popularized by N.S. Yanofsky (2003), based on a pioneering work of F.W. Lawvere (1969), in which the existence of a (diagonolized-out and contradictory) object implies the existence of a fixed-point for a certain function. It was shown that many self-referential paradoxes and diagonally proved theorems can fit in that schema. Here, we fit more theorems in the universal
schema of diagonalization, such as Euclid's proof for the infinitude of the primes and new proofs of G.~Boolos (1997) for Cantor's theorem on the non-equinumerosity of a set with its powerset. Then, in Linear Temporal Logic, we show the non-existence of a fixed-point in this logic whose proof resembles the argument of Yablo's paradox (1985, 1993). Thus, Yablo's paradox turns for the first time into a genuine mathematico-logical theorem in the framework of Linear Temporal Logic. Again the diagonal schema of the paper is used in this proof; and it is also shown that G.~Priest's inclosure schema (1997) can fit in our universal diagonal/fixed-point schema. We also show the existence of dominating (Ackermann-like) functions (which dominate a given countable set of functions, such as primitive recursive functions) in the schema.Sat, 30 Sep 2017 20:30:00 +0100On two classes of third order boundary value problems with finite spectrum
http://iranjournals.nlai.ir/1174/article_315340_43645.html
The spectral analysis of two classes of third order boundary value problems is investigated. For every positive integer $m$ we construct two classes of regular third order boundary value problems with at most $2m+1$ eigenvalues, counting multiplicity. These kinds of finite spectrum results are previously known only for even order boundary value problems.Sat, 30 Sep 2017 20:30:00 +0100Affinization of Segre products of partial linear spaces
http://iranjournals.nlai.ir/1174/article_315341_43645.html
Hyperplanes and hyperplane complements in the Segre product of partial linear spaces are investigated. The parallelism of such a complement is characterized in terms of the point-line incidence. Assumptions, under which the automorphisms of the complement are the restrictions of the automorphisms of the ambient space, are given. An affine covering for the Segre product of Veblenian gamma spaces is established. A general construction that produces non-degenerate hyperplanes in the Segre product of partial linear spaces embeddable into projective space is introduced.Mon, 30 Oct 2017 20:30:00 +0100A new one-step iterative process for approximating common fixed points of a countable family of ...
http://iranjournals.nlai.ir/1174/article_315342_43645.html
In this paper, we propose a new one-step iterative process for a countable family of quasi-nonexpansive multi-valued mappings in a CAT(0) space. We also prove strong and $Delta$-convergence theorems of the proposed iterative process under some control conditions. Our main results extend and generalize many results in the literature.Sat, 30 Sep 2017 20:30:00 +0100A new characterization of $L_2(q)$ by the largest element orders
http://iranjournals.nlai.ir/1174/article_315343_43645.html
We characterize the finite simple groups $L_2(q)$ by the group orders and the largest element orders, where $q$ is a prime or $q=2^a$, with $2^a+1$ or $2^a-1$ a prime.Mon, 30 Oct 2017 20:30:00 +0100A radical extension of the category of $S$-sets
http://iranjournals.nlai.ir/1174/article_315344_43645.html
Let S-Set be the category of $S$-sets, sets together with the actions of a semigroup $S$ on them. And, let S-Pos be the category of $S$-posets, posets together with the actions compatible with the orders on them. In this paper we show that the category S-Pos is a radical extension of S-Set; that is there is a radical on the category S-Pos, the order desolator radical, whose torsion-free class is S-Set. To do this, first we give a precise definition of a radical on the category S-Posand construct some functors between the above mentioned categories and finally we show that S-Pos is a radical extension of S-Set.Mon, 30 Oct 2017 20:30:00 +0100A numerical method for discrete fractional--order chemostat model derived from nonstandard ...
http://iranjournals.nlai.ir/1174/article_315345_43645.html
In this paper, the fractional--order form of three dimensional chemostat model with variable yields is introduced. The stability analysis of this fractional system is discussed in detail. In order to study the dynamic behaviours of the mentioned fractional system, the well known nonstandard (NSFD) scheme is implemented. The proposed NSFD scheme is compared with the forward Euler and fourth order Runge--Kutta methods. Numerical results show that the NSFD approach is easy and accurate when applied to fractional--order chemostat model.Mon, 30 Oct 2017 20:30:00 +0100On characterizations of hyperbolic harmonic Bloch and Besov spaces
http://iranjournals.nlai.ir/1174/article_315346_43645.html
We define hyperbolic harmonic $omega$-$alpha$-Bloch space $mathcal{B}_omega^alpha$ in the unit ball $mathbb{B}$ of ${mathbb R}^n$ and characterize it in terms of $$frac{omegabig((1-|x|^2)^{beta}(1-|y|^2)^{alpha-beta}big)|f(x)-f(y)|}{[x,y]^gamma|x-y|^{1-gamma}},$$ where $0leq gammaleq 1$. Similar results are extended to little $omega$-$alpha$-Bloch and Besov spaces. These obtained characterizations generalize the corresponding ones which were obtained by G. Ren and U. K{a}hler in 2002 and 2005.Mon, 30 Oct 2017 20:30:00 +0100On the character space of Banach vector-valued function algebras
http://iranjournals.nlai.ir/1174/article_315347_43645.html
Given a compact space $X$ and a commutative Banach algebra $A$, the character spaces of $A$-valued function algebras on $X$ are investigated. The class of natural $A$-valued function algebras, those whose characters can be described by means of characters of $A$ and point evaluation homomorphisms, is introduced and studied. For an admissible Banach $A$-valued function algebra $mathscr{A}$ on $X$, conditions under which the character space $mathfrak{M}(mathscr{A})$ is homeomorphic to $mathfrak{M}(mathfrak{A})times mathfrak{M}(A)$ are presented, where $mathfrak{A}=C(X) capmathscr{A}$ is the subalgebra of $mathscr{A}$ consisting of scalar-valued functions. An illustration of the results is given by some examples.Mon, 30 Oct 2017 20:30:00 +0100On some generalized recurrent manifolds
http://iranjournals.nlai.ir/1174/article_315348_43645.html
The object of the present paper is to introduce and study a type of non-flat semi-Riemannian manifolds, called, super generalized recurrent manifolds which generalizes both the notion of hyper generalized recurrent manifolds [A.A. Shaikh and A. Patra, On a generalized class of recurrent manifolds, Arch. Math. (Brno) 46 (2010) 71--78.] and weakly generalized recurrent manifolds [A.A. Shaikh and I. Roy, On weakly generalized recurrent manifolds, Ann. Univ. Sci. Budapest Rolando Eotvos, Sect. Math. 54 (2011) 35--45.]. The nature of associated 1-forms of a super generalized recurrent manifold is determined and it is proved that on a Roter type manifold [R. Deszcz, On Roter type manifolds, in: 5th Conference on Geometry and Topology of Manifolds, Krynica, Poland, 2003.] such a notion is equivalent to the notion of generalized Ricci-recurrent manifold [U.C. De, N. Guha and D. Kamilya, On generalized Ricci-recurrent manifolds, Tensor (N.S.) 56 (1995), no. 3, 312--317.]. We also obtain a sufficient condition for a super generalized recurrent manifold to be a semisymmetric one and the existence of such notion is ensured by a proper example.Mon, 30 Oct 2017 20:30:00 +0100A study on dimensions of modules
http://iranjournals.nlai.ir/1174/article_315349_43645.html
In this article we study relations between some algebraic operations such as tensor product and localization from one hand and some well-known dimensions such as uniform dimension, hollow dimension and type dimension from the other hand. Some minor applications to the ring $C(X)$ are observed.Mon, 30 Oct 2017 20:30:00 +0100On pm$^+$ and finite character bi-amalgamation
http://iranjournals.nlai.ir/1174/article_315350_43645.html
Let $f:Arightarrow B$ and $g:A rightarrow C$ be two ring homomorphisms and let $J$ and $J^{'}$ be two ideals of $B$ and $C$, respectively, such that $f^{-1}(J)=g^{-1}(J^{'})$. The bi-amalgamation of $A$ with $(B,C)$ along $(J,J^{'})$ with respect of $(f,g)$ is the subring of $Btimes C$ given by $Abowtie^{f,g}(J,J^{'})={(f(a)+j,g(a)+j^{'})/ a in A, (j,j^{'}) in Jtimes J^{'}}.$ In this paper, we study the transference of $pm^{+}$, $pm$ and finite character ring-properties in the bi-amalgamation.Mon, 30 Oct 2017 20:30:00 +0100Efficient quadrature rules for a class of cordial Volterra integral equations: A comparative study
http://iranjournals.nlai.ir/1174/article_315351_43645.html
A natural algorithm with an optimal order of convergence is proposed for numerical solution of a class of cordial weakly singular Volterra integral equations. The equations of this class appear in heat conduction problems with mixed boundary conditions. The algorithm is based on a representation of the solution and compound Gaussian quadrature rules with graded meshes. A comparative study is carried out, which points out that the proposed method is the most efficient one among other existing methods. In fact, the results of this paper introduce a most-efficient decisive-choice for computing the solution of the heat conduction model.Sat, 30 Sep 2017 20:30:00 +0100On certain maximality principles
http://iranjournals.nlai.ir/1174/article_315352_43645.html
We present streamlined proofs of certain maximality principles studied by Hamkins and Woodin. Moreover, we formulate an intermediate maximality principle, which is shown here to be equiconsistent with the existence of a weakly compact cardinal $kappa$ such that $V_{kappa}prec V$.Mon, 30 Oct 2017 20:30:00 +0100Application of frames in Chebyshev and conjugate gradient methods
http://iranjournals.nlai.ir/1174/article_315353_43645.html
Given a frame of a separable Hilbert space $H$, we present some iterative methods for solving an operator equation $Lu=f$, where $L$ is a bounded, invertible and symmetric operator on $H$. We present some algorithms based on the knowledge of frame bounds, Chebyshev method and conjugate gradient method, in order to give some approximated solutions to the problem. Then we investigate the convergence and optimality of them.Mon, 30 Oct 2017 20:30:00 +0100Further inequalities for operator space numerical radius on 2*2 operator matrices
http://iranjournals.nlai.ir/1174/article_315354_43645.html
We present some inequalities for operator space numerical radius of $2times 2$ block matrices on the matrix space $mathcal{M}_n(X)$, when $X$ is a numerical radius operator space. These inequalities contain some upper and lower bounds for operator space numerical radius.Mon, 30 Oct 2017 20:30:00 +0100Stochastic evolution equations with multiplicative Poisson noise and monotone nonlinearity
http://iranjournals.nlai.ir/1174/article_315355_43645.html
Semilinear stochastic evolution equations with multiplicative Poisson noise and monotone nonlinear drift in Hilbert spaces are considered. The coefficients are assumed to have linear growth. We do not impose coercivity conditions on coefficients. A novel method of proof for establishing existence and uniqueness of the mild solution is proposed. Examples on stochastic partial differential equations and stochastic delay differential equations are provided to demonstrate the theory developed.Sat, 30 Sep 2017 20:30:00 +0100Improvements of Young inequality using the Kantorovich constant
http://iranjournals.nlai.ir/1174/article_315356_43645.html
Some improvements of Young inequality and its reverse for positive numbers with Kantorovich constant $K(t, 2)=frac{(1+t)^2}{4t}$ are given. Using these inequalities some operator inequalities and Hilbert-Schmidt norm versions for matrices are proved. In particular, it is shown that if $a, b$ are positive numbers and $0 leqslant nu leqslant 1,$ then for all integers $ kgeqslant 1: $ $K(h^{frac{1}{2^n}},2)^{r_n} asharp_{nu}b leqslant anabla_{nu} b - sum_{k=0}^{n-1}r_{k}left((a sharp_{frac{m_k}{2^k}} b )^{frac{1}{2}}- (a sharp_{frac{m_k+1}{2^k}}b )^{frac{1}{2}}right)^{2}leqslant K(h^{frac{1}{2^n}},2)^{R_n} asharp_{nu}b,$ where $m_k= [ 2^knu ] $ is the largest integer not greater than $2^knu$, $ r_0=min { nu, 1-nu}, $ $ _{k}=min { 2r_{k-1}, 1-2r_{k-1} } $ and $R_k=1-r_k$.Mon, 30 Oct 2017 20:30:00 +0100Dilations for $C^ast$-dynamical systems with abelian groups on Hilbert $C^ast$-modules
http://iranjournals.nlai.ir/1174/article_315357_43645.html
In this paper we investigate the dilations of completely positive definite representations of (C^ast)-dynamical systems with abelian groups on Hilbert (C^ast)-modules. We show that if ((mathcal{A}, G,alpha)) is a (C^ast)-dynamical system with (G) an abelian group, then every completely positive definite covariant representation ((pi,varphi,E)) of ((mathcal{A}, G,alpha)) on a Hilbert (C^ast)-module (E) admits an unitary dilation $((hat{pi},hat{varphi},hat{E})).$Mon, 30 Oct 2017 20:30:00 +0100Some topologies on the space of quasi-multipliers
http://iranjournals.nlai.ir/1174/article_315358_43645.html
Assume that $A$ is a Banach algebra. We define the $beta-$topology and the $gamma-$topology on the space $QM_{el}(A^{*})$ of all bounded extended left quasi-multipliers of $A^{*}.$ We establish further properties of $(QM_{el}(A^{*}),gamma)$ when $A$ is a $C^{*}-$algebra. In particular, we characterize the $gamma-$dual of $QM_{el}(A^{*})$ and prove that $(QM_{el}(A^{*}),gamma)^{*},$ under the topology of bounded convergence, is isomorphic to $A^{***}.$Mon, 30 Oct 2017 20:30:00 +0100Strongly nil-clean corner rings
http://iranjournals.nlai.ir/1174/article_315359_43645.html
We show that if $R$ is a ring with an arbitrary idempotent $e$ such that $eRe$ and $(1-e)R(1-e)$ are both strongly nil-clean rings, then $R/J(R)$ is nil-clean. In particular, under certain additional circumstances, $R$ is also nil-clean. These results somewhat improves on achievements due to Diesl in J. Algebra (2013) and to Koc{s}an-Wang-Zhou in J. Pure Appl. Algebra (2016). In addition, we also give a new transparent proof of the main result of Breaz-Calugareanu-Danchev-Micu in Linear Algebra Appl. (2013) which says that if $R$ is a commutative nil-clean ring, then the full $ntimes n$ matrix ring $mathbb{M}_n(R)$ is nil-clean.Mon, 30 Oct 2017 20:30:00 +0100Inverse Sturm--Liouville problems using three spectra with finite number of transmissions and ...
http://iranjournals.nlai.ir/1174/article_315360_43645.html
In this manuscript, we study various by uniqueness results for inverse spectral problems of Sturm--Liouville operators using three spectrum with a finite number of discontinuities at interior points which we impose the usual transmission conditions. We consider both the cases of classical Robin and eigenparameter dependent boundary conditions.Mon, 30 Oct 2017 20:30:00 +0100Convergence of the sinc method applied to delay Volterra integral equations
http://iranjournals.nlai.ir/1174/article_315361_43645.html
In this paper, the numerical solutions of linear and nonlinear Volterra integral equations with nonvanishing delay are considered by two methods. The methods are developed by means of the sinc approximation with the single exponential (SE) and double exponential (DE) transformations. The existence and uniqueness of sinc-collocation solutions for these equations are provided. These methods improve conventional results and achieve exponential convergence. Numerical results are included to confirm the efficiency and accuracy of the methods.Mon, 30 Oct 2017 20:30:00 +0100A stochastic version analysis of an M/G/1 retrial queue with Bernoulli schedule
http://iranjournals.nlai.ir/1174/article_315362_43645.html
In this work, we derive insensitive bounds for various performance measures of a single-server retrial queue with generally distributed inter-retrial times and Bernoulli schedule, under the special assumption that only the customer at the head of the orbit queue (i.e., a FCFS discipline governing the flow from the orbit to the server) is allowed to occupy the server. The methodology is strongly based on stochastic comparison techniques. Instead of studying a performance measure in a quantitative fashion, this approach attempts to reveal the relationship between the performance measures and the parameters of the system. We prove the monotonicity of the transition operator of the embedded Markov chain relative to strong stochastic ordering and increasing convex ordering. We obtain comparability conditions for the distribution of the number of customers in the system. Bounds are derived for the stationary distribution and some simple bounds for the mean characteristics of the system. The proofs of these results are based on the validation of some inequalities for some cumulative probabilities associated with every state $(m, n)$ of the system. Finally, the effects of various parameters on the performance of the system have been examined numerically.Mon, 30 Oct 2017 20:30:00 +0100An algorithm for approximating nondominated points of convex multiobjective optimization problems
http://iranjournals.nlai.ir/1174/article_315363_43645.html
In this paper, we present an algorithm for generating approximate nondominated points of a multiobjective optimization problem (MOP), where the constraints and the objective functions are convex. We provide outer and inner approximations of nondominated points and prove that inner approximations provide a set of approximate weakly nondominated points. The proposed algorithm can be applied for differentiable or nondifferentiable convex MOPs. To illustrate efficiency of the proposed algorithm for convex MOPs, we provide numerical examples.Mon, 30 Oct 2017 20:30:00 +0100Complete pivoting strategy for the $IUL$ preconditioner obtained from Backward Factored ...
http://iranjournals.nlai.ir/1174/article_315364_43645.html
In this paper, we use a complete pivoting strategy to compute the IUL preconditioner obtained as the by-product of the Backward Factored APproximate INVerse process. This pivoting is based on the complete pivoting strategy of the Backward IJK version of Gaussian Elimination process. There is a parameter $alpha$ to control the complete pivoting process. We have studied the effect of different values of $alpha$ on the quality of the IUL preconditioner. For the numerical experiments section, the IUL factorization which is coupled with the complete pivoting is compared to the ILUTP and to the left-looking version of RIF which is coupled with the complete pivoting strategy. As the preprocessing, we have applied the maximum weighted matching coupled the Reverse Cuthill-Mckee (RCM) and multilevel nested dissection reordering.Mon, 30 Oct 2017 20:30:00 +0100Very cleanness of generalized matrices
http://iranjournals.nlai.ir/1174/article_315365_43645.html
An element $a$ in a ring $R$ is very clean in case there exists an idempotent $ein R$ such that $ae = ea$ and either $a- e$ or $a + e$ is invertible. An element $a$ in a ring $R$ is very $J$-clean provided that there exists an idempotent $ein R$ such that $ae = ea$ and either $a-ein J(R)$ or $a + ein J(R)$. Let $R$ be a local ring, and let $sin C(R)$. We prove that $Ain K_s(R)$ is very clean if and only if $Ain U(K_s(R))$, $Ipm Ain U(K_s(R))$ or $Ain K_s(R)$ is very J-clean.Mon, 30 Oct 2017 20:30:00 +0100Five-value rich lines, Borel directions and uniqueness of meromorphic functions
http://iranjournals.nlai.ir/1174/article_315366_43645.html
For a meromorphic function $f$ in the complex plane, we shall introduce the definition of five-value rich line of $f$, and study the uniqueness of meromorphic functions of finite order in an angular domain by involving the five-value rich line and Borel directions. Finally, the relationship between a five-value rich line and a Borel direction is discussed, that is, every Borel direction of $f$ is its five-value rich line, and the inverse statement holds when $f$ is of infinite order.Mon, 30 Oct 2017 20:30:00 +0100Some rank equalities for finitely many tripotent matrices
http://iranjournals.nlai.ir/1174/article_315367_43645.html
A rank equality is established for the sum of finitely many tripotent matrices via elementary block matrix operations. Moreover, by using this equality and Theorems 8 and 10 in [Chen M. and et al. On the open problem related to rank equalities for the sum of finitely many idempotent matrices and its applications, The Scientific World Journal 2014 (2014), Article ID 702413, 7 pages.], some other rank equalities for tripotent matrices are given. Furthermore, we obtain several rank equalities related to some special types of matrices, some of which are available in the literature, from the results established.Mon, 30 Oct 2017 20:30:00 +0100Convex combinations of harmonic shears of slit mappings
http://iranjournals.nlai.ir/1174/article_315368_43645.html
In this paper, we study the convex combinations of harmonic mappings obtained by shearing a class of slit conformal mappings. Sufficient conditions for the convex combinations of harmonic mappings of this family to be univalent and convex in the horizontal direction are derived. Several examples of univalent harmonic mappings constructed by using these methods are presented to illustrate potential applications of the main results.Mon, 30 Oct 2017 20:30:00 +0100On a p-Laplacian system and a generalization of the Landesman-Lazer type condition
http://iranjournals.nlai.ir/1174/article_315369_43645.html
This article shows the existence of weak solutions of a resonance problem for nonuniformly p-Laplacian system in a bounded domain in $mathbb{R}^N$. Our arguments are based on the minimum principle and rely on a generalization of the Landesman-Lazer type condition.Mon, 30 Oct 2017 20:30:00 +0100A simple proof of Zariski's Lemma
http://iranjournals.nlai.ir/1174/article_315370_43645.html
Our aim in this very short note is to show that the proof of the following well-known fundamental lemma of Zariski follows from an argument similar to the proof of the fact that the rational field $mathbb{Q}$ is not a finitely generated $mathbb{Z}$-algebra.Mon, 30 Oct 2017 20:30:00 +0100NSE characterization of some linear groups
http://iranjournals.nlai.ir/1174/article_315371_43645.html
For a finite group $G$, let $nse(G)={m_kmid kinpi_e(G)}$, where $m_k$ is the number of elements of order $k$ in $G$ and $pi_{e}(G)$ is the set of element orders of $G$. In this paper, we prove that $Gcong L_m(2)$ if and only if $pmid |G|$ and $nse(G)=nse(L_m(2))$, where $min {n,n+1}$ and $2^n-1=p$ is a prime number.Mon, 30 Oct 2017 20:30:00 +0100Measure of non strict singularity of Schechter essential spectrum of two bounded operators and ...
http://iranjournals.nlai.ir/1174/article_315372_43645.html
In this paper, we discuss the essential spectrum of sum of two bounded operators using measure of non strict singularity. Based on this new investigation, a problem of one-speed neutron transport operator is presented.Sat, 30 Sep 2017 20:30:00 +0100