Iranian Journal of Mathematical Sciences and Informatics
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Iranian Journal of Mathematical Sciences and Informatics - Journal articles for year 2014, Volume 9, Number 2Yektaweb Collection - http://www.yektaweb.comen2014/11/10On Generalized Coprime Graphs
http://ijmsi.ir/browse.php?a_id=319&sid=1&slc_lang=en
<div style="TEXT-ALIGN: left">Paul Erdos defined the concept of coprime graph and studied about cycles in coprime graphs. In this paper this concept is generalized and a new graph called Generalized coprime graph is introduced. Having observed certain basic properties of the new graph it is proved that the chromatic number and the clique number of some generalized coprime graphs are equal.</div>
S. MutharasuLocal Cohomology with Respect to a Cohomologically Complete Intersection Pair of Ideals
http://ijmsi.ir/browse.php?a_id=640&sid=1&slc_lang=en
<p>Let $(R,fm,k)$ be a local Gorenstein ring of dimension $n$. Let $H_{I,J}^i(R)$ be theĀ local cohomology with respect to a pair of ideals $I,J$ and $c$ be the $inf{i|H_{I,J}^i(R)neq0}$. A pair of ideals $I, J$ is called cohomologically complete intersection if $H_{I,J}^i(R)=0$ for all $ineq c$. It is shown that, when $H_{I,J}^i(R)=0$ for all $ineq c$, (i) a minimal injective resolution of $H_{I,J}^c(R)$ presents like that of a Gorenstein ring (ii) $Hom_R(H_{I,J}^c(R),H_{I,J}^c(R))simeq R$, where $(R,fm)$ is a complete ring. Also we get an estimate of theĀ dimension of $H_{I,J}^i(R)$.</p>
A. Pour Eshmanan TalemiStrongly almost ideal convergent sequences in a locally convex space defined by Musielak-Orlicz function
http://ijmsi.ir/browse.php?a_id=522&sid=1&slc_lang=en
<p>In this article, we introduce a new class of ideal convergent sequence spaces using an infinite matrix, Musielak-Orlicz function and a new generalized difference matrix in locally convex spaces. We investigate some linear topological structures and algebraic properties of these spaces. We also give some relations related to these sequence spaces.</p>
B. HazarikaThe p-median and p-center Problems on Bipartite Graphs
http://ijmsi.ir/browse.php?a_id=641&sid=1&slc_lang=en
<p>Let $G$ be a bipartite graph. In this paper we consider the two kind of location problems namely $p$-center and $p$-median problems on bipartite graphs. The $p$-center and $p$-median problems asks to find a subset of vertices of cardinality $p$, so that respectively the maximum and sum of the distances from this set to all other vertices in $G$ is minimized. For each case we present some properties to find exact solutions.</p>
J. FathaliChromaticity of Turan Graphs with At Most Three Edges Deleted
http://ijmsi.ir/browse.php?a_id=642&sid=1&slc_lang=en
<p>Let $P(G,lambda)$ be the chromatic polynomial of a graph $G$. A graph $G$ ischromatically unique if for any graph $H$, $P(H, lambda) = P(G,lambda)$ implies $H$ is isomorphic to $G$. In this paper, we determine the chromaticity of all Tur'{a}n graphs with at most three edges deleted. As a by product, we found many families of chromatically unique graphs and chromatic equivalence classes of graphs.</p>
S. AlikhaniA Semidefinite Optimization Approach to Quadratic Fractional Optimization with a Strictly Convex Quadratic Constraint
http://ijmsi.ir/browse.php?a_id=643&sid=1&slc_lang=en
<p>In this paper we consider a fractional optimization problem that minimizes the ratio of two quadratic functions subject to a strictly convex quadratic constraint. First using the extension of Charnes-Cooper transformation, an equivalent homogenized quadratic reformulation of the problem is given. Then we show that under certain assumptions, it can be solved to global optimality using semidefinite optimization relaxation in polynomial time.</p>
M. SalahiOn Some Fractional Systems of Difference Equations
http://ijmsi.ir/browse.php?a_id=524&sid=1&slc_lang=en
<p>This paper deal with the solutions of the systems of difference equations $$x_{n+1}=frac{y_{n-3}y_nx_{n-2}}{y_{n-3}x_{n-2}pm y_{n-3}y_n pm y_nx_{n-2}}, ,y_{n+1}=frac{y_{n-2}x_{n-1}}{ 2y_{n-2}pm x_{n-1}},,nin mathbb{N}_{0},$$ where $mathbb{N}_{0}=mathbb{N}cup left{0right}$, and initial values $x_{-2},, x_{-1},,x_{0},,y_{-3},,y_{-2},,y_{-1},,y_{0}$ are non-zero real numbers.</p>
N. TouafekSome Results on Convexity and Concavity of Multivariate Copulas
http://ijmsi.ir/browse.php?a_id=644&sid=1&slc_lang=en
<p>This paper provides some results on different types of convexity and concavity in the class of multivariate copulas. We also study their properties and provide several examples to illustrate our results.</p>
A. Dehgan NezhadApplication of the Norm Estimates for Univalence of Analytic Functions
http://ijmsi.ir/browse.php?a_id=377&sid=1&slc_lang=en
<p>By using norm estimates of the pre-Schwarzian derivatives for certain family of analytic functions, we shall give simple sufficient conditions for univalence of analytic functions.</p>
R. AghalaryOn the Ultramean Construction
http://ijmsi.ir/browse.php?a_id=391&sid=1&slc_lang=en
<p>We use the ultramean construction to prove linear compactness theorem. We also extend the Rudin-Keisler ordering to maximal probability charges and characterize it by embeddings of power ultrameans.</p>
M. BagheriABSTRACTS IN PERSIAN - Vol. 9, No. 2
http://ijmsi.ir/browse.php?a_id=843&sid=1&slc_lang=en
<p>Please see the full text contains the Pesian abstracts for this volume.</p>
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