Bulletin of the Iranian Mathematical Society
text
article
2014
eng
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
http://bims.iranjournals.ir/article_532_8dd7670ec7eb6c5d19ad0ed9e3024589.pdf
A full Nesterov-Todd step infeasible interior-point algorithm for symmetric cone linear complementarity problem
Behrouz
Kheirfam
Azarbaijan university of tarbiat moallem
author
N.
Mahdavi-Amiri
Sharif University of Technology
author
text
article
2014
eng
A full Nesterov-Todd (NT) step infeasible interior-point algorithm is proposed for solving monotone linear complementarity problems over symmetric cones by using Euclidean Jordan algebra. Two types of full NT-steps are used, feasibility steps and centering steps. The algorithm starts from strictly feasible iterates of a perturbed problem, and, using the central path and feasibility steps, finds strictly feasible iterates for the next perturbed problem. By using centering steps for the new perturbed problem, strictly feasible iterates are obtained to be close enough to the central path of the new perturbed problem. The starting point depends on two positive numbers $rho_p$ and $rho_d$. The algorithm terminates either by finding an $epsilon$-solution or detecting that the symmetric cone linear complementarity problem has no optimal solution with vanishing duality gap satisfying a condition in terms of $rho_p$ and $rho_d$. The iteration bound coincides with the best known bound for infeasible interior-point methods.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
541
564
http://bims.iranjournals.ir/article_515_87dae336a5454d821bb5fe6a798ce8d4.pdf
Actions of vector groupoids
Mustafa
Gursoy
Inonu University, Science and Art Faculty, Department of Mathematics
author
text
article
2014
eng
In this work we deal with actions of vector groupoid which is a new concept in the literature. After we give the definition of the action of a vector groupoid on a vector space, we obtain some results related to actions of vector groupoids. We also apply some characterizations of the category and groupoid theory to vector groupoids. As the second part of the work, we define the notion of a crossed module over a vector groupoid. Finally, we show that the category $mathcal{VG}$ of the vector groupoids is equivalent to the category $mathcal{CM}odmathcal{VG}$ of the crossed modules over a vector groupoid.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
565
583
http://bims.iranjournals.ir/article_516_a061a08b4f697cdd15e357519ec9d8fc.pdf
On inverse problem for singular Sturm-Liouville operator with discontinuity conditions
Rauf
Amirov
Cumhuriyet University
author
Nilufer
Topsakal
Cumhuriyet University
author
text
article
2014
eng
In this study, properties of spectral characteristic are investigated for singular Sturm-Liouville operators in the case where an eigen parameter not only appears in the differential equation but is also linearly contained in the jump conditions. Also Weyl function for considering operator has been defined and the theorems which related to uniqueness of solution of inverse problem according to Weyl function and two spectra have been proved.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
585
607
http://bims.iranjournals.ir/article_517_0a62f112571ba18fef364301e1508bd5.pdf
Cohen-Macaulay $r$-partite graphs with minimal clique cover
Asghar
Madadi
University of Zanjan
author
Rashid
Zaare-Nahandi
Institute for Advanced Studies in Basic Sciences
author
text
article
2014
eng
In this paper, we give some necessary conditions for an $r$-partite graph such that the edge ring of the graph is Cohen-Macaulay. It is proved that if there exists a cover of an $r$-partite Cohen-Macaulay graph by disjoint cliques of size $r$, then such a cover is unique.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
609
617
http://bims.iranjournals.ir/article_518_74456fc52a61f817f7e2e1c754c4e297.pdf
Almost sure exponential stability of stochastic reaction diffusion systems with Markovian jump
Jun
Liu
Department of Mathematics, Jining University
author
text
article
2014
eng
The stochastic reaction diffusion systems may suffer sudden shocks, in order to explain this phenomena, we use Markovian jumps to model stochastic reaction diffusion systems. In this paper, we are interested in almost sure exponential stability of stochastic reaction diffusion systems with Markovian jumps. Under some reasonable conditions, we show that the trivial solution of stochastic reaction diffusion systems with Markovian jumps is almost surely exponentially stable. An example is given to illustrate the theory.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
619
629
http://bims.iranjournals.ir/article_519_891f0ad28cefb412975dd1830d236797.pdf
Singular value inequalities for positive semidefinite matrices
Limin
Zou
School of Mathematics and Statistics, Chongqing Three Gorges University, Chongqing, 404100, P. R. China
author
Youyi
Jiang
School of Mathematics and Statistics, Chongqing Three Gorges University, Chongqing, 404100, P. R. China
author
text
article
2014
eng
In this note, we obtain some singular values inequalities for positive semidefinite matrices by using block matrix technique. Our results are similar to some inequalities shown by Bhatia and Kittaneh in [Linear Algebra Appl. 308 (2000) 203-211] and [Linear Algebra Appl. 428 (2008) 2177-2191].
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
631
638
http://bims.iranjournals.ir/article_520_c71637e5b1df06a1de18254b7a143de5.pdf
On the category of geometric spaces and the category of (geometric) hypergroups
Morteza
Jafarpour
fACULTY OF MATHEMATICS
author
Seyed Shahin
Mousavi
Faculty of Math.
author
text
article
2014
eng
In this paper first we define the morphism between geometric spaces in two different types. We construct two categories of $uu$ and $l$ from geometric spaces then investigate some properties of the two categories, for instance $uu$ is topological. The relation between hypergroups and geometric spaces is studied. By constructing the category $qh$ of $H_{v}$-groups we answer the question that which construction of hyperstructures on the category of sets has free object in the sense of universal property. At the end we define the category of geometric hypergroups and we study its relation with the category of hypergroup.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
639
655
http://bims.iranjournals.ir/article_521_009238c4d65b14d487336590f1f19d41.pdf
On $z$-ideals of pointfree function rings
Themba
Dube
University of South Africa
author
Oghenetega
Ighedo
University of South Africa (Unisa)
author
text
article
2014
eng
Let $L$ be a completely regular frame and $mathcal{R}L$ be the ring of continuous real-valued functions on $L$. We show that the lattice $Zid(mathcal{R}L)$ of $z$-ideals of $mathcal{R}L$ is a normal coherent Yosida frame, which extends the corresponding $C(X)$ result of Mart'{i}nez and Zenk. This we do by exhibiting $Zid(mathcal{R}L)$ as a quotient of $Rad(mathcal{R}L)$, the frame of radical ideals of $mathcal{R}L$. The saturation quotient of $Zid(mathcal{R}L)$ is shown to be isomorphic to the Stone-v{C}ech compactification of $L$. Given a morphism $hcolon Lto M$ in $mathbf{CRegFrm}$, $Zid$ creates a coherent frame homomorphism $Zid(h)colonZid(mathcal{R}L)toZid(mathcal{R}M)$ whose right adjoint maps as $(mathcal{R}h)^{-1}$, for the induced ring homomorphism $mathcal{R}hcolonmathcal{R}Ltomathcal{R}M$.Thus, $Zid(h)$ is an $s$-map, in the sense of Mart`{i}nez cite{Mar1}, precisely when $mathcal{R}(h)$ contracts maximal ideals to maximal ideals.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
657
675
http://bims.iranjournals.ir/article_522_1fe5585962e54ee9e2c852914314378a.pdf
When every $P$-flat ideal is flat
Fatima
Cheniour
Department of Mathematics, FST, University of Fez
author
Najib
Mahdou
Department of Mathematics, Faculty of Sciences and Technology, University of Fez, Fez, Morocco.
author
text
article
2014
eng
In this paper, we study the class of rings in which every $P$-flat ideal is flat and which will be called $PFF$-rings. In particular, Von Neumann regular rings, hereditary rings, semi-hereditary ring, PID and arithmetical rings are examples of $PFF$-rings. In the context domain, this notion coincide with Pr"{u}fer domain. We provide necessary and sufficient conditions for $R=Apropto E $ to be a $PFF$-ring where $A$ is a domain and $E$ is a $K$-vector space, where $K:=qf(A)$ or $A$ is a local ring such that $ME:=0$. We give examples of non-$fqp$ $PFF$-ring, of non-arithmetical $PFF$-ring, of non-semihereditary $PFF$-ring, of $PFF$-ring with $wgldim>1$ and of non-$PFF$ Pr"{u}fer-ring. Also, we investigate the stability of this property under localization and homomorphic image, and its transfer to finite direct products. Our results generate examples which enrich the current literature with new and original families of rings that satisfy this property.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
677
688
http://bims.iranjournals.ir/article_523_d6d550a815d948c112a45d8e9bbc1778.pdf
On the existence of fixed points for contraction mappings depending on two functions
José
Morales
Universidad de Los Andes
author
Edixon
Rojas
pontificia universidad javeriana
author
text
article
2014
eng
In this paper we study the existence of fixed points for mappings defined on complete metric spaces, satisfying a general contractive inequality depending on two additional mappings.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
689
698
http://bims.iranjournals.ir/article_524_ef17e0d1cebfa29cd07c1c91ff75e04b.pdf
A finite difference technique for solving variable-order fractional integro-differential equations
Yufeng
Xu
Department of Applied Mathematics, Central South University, Changsha, People’s
Republic of China
author
Vedat
Suat Ertürk
Department of Mathematics, Faculty of Arts and Sciences, Ondokuz Mayıs University, 55139, Samsun, Turkey
author
text
article
2014
eng
In this article, we use a finite difference technique to solve variable-order fractional integro-differential equations (VOFIDEs, for short). In these equations, the variable-order fractional integration(VOFI) and variable-order fractional derivative (VOFD) are described in the Riemann-Liouville's and Caputo's sense,respectively. Numerical experiments, consisting of two examples, are studied. The obtained numerical results reveal that the proposed finite difference technique is very effective and convenient for solving VOFIDEs.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
699
712
http://bims.iranjournals.ir/article_525_7ec20c508b2c270421866bc02cdaf7d3.pdf
About remainders in compactifications of paratopological groups
Fucai
Lin
Minnan Normal University
author
Shou
Lin
Ningde Teachers' College
author
text
article
2014
eng
In this paper, we prove a dichotomy theorem for remainders in compactifications of paratopological groups: every remainder of a paratopological group $G$ is either Lindel"{o}f and meager or Baire. Furthermore, we give a negative answer to a question posed in [D. Basile and A. Bella, About remainders in compactifications of homogeneous spaces, Comment. Math. Univ. Carolin. 50 (2009), no. 4, 607--613]. Some questions about remainders in compactifications of paratopological groups are posed.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
713
719
http://bims.iranjournals.ir/article_526_b50bc3b4aceff528fbb77c87aad819b1.pdf
Cat$^1$-polygroups and pullback cat$^1$-polygroups
Bijan
Davvaz
Yazd University
author
Murat
Alp
Nigde Universit
author
text
article
2014
eng
In this paper, we give the notions of crossed polymodule and cat$^1$-polygroup as a generalization of Loday's definition. Then, we define the pullback cat$^1$-polygroup and we obtain some results in this respect. Specially, we prove that by a pullback cat$^1$-polygroup we can obtain a cat$^1$-group.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
721
735
http://bims.iranjournals.ir/article_527_6286c7397d9d3edb57e3007f8052de19.pdf
A family of large set of size nine
Mojgan
Emami
University of Zanjan
author
Ozra
Naserian
University of zanjan
author
text
article
2014
eng
We investigate the existence of some large sets of size nine. The large set $LS[9](2,5,29)$ is constructed and existence of the family $LS[9](2,5,27l+j)$ for $lgeq 1, 2leq j<5$ are proved.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
737
749
http://bims.iranjournals.ir/article_528_827186200edcc7ed910550ae6b483f5c.pdf
$k$-tuple total restrained domination/domatic in graphs
Adel
P. Kazemi
University of Mohaghegh Ardabili
author
text
article
2014
eng
For any integer $kgeq 1$, a set $S$ of vertices in a graph $G=(V,E)$ is a $k$-tuple total dominating set of $G$ if any vertex of $G$ is adjacent to at least $k$ vertices in $S$, and any vertex of $V-S$ is adjacent to at least $k$ vertices in $V-S$. The minimum number of vertices of such a set in $G$ we call the $k$-tuple total restrained domination number of $G$. The maximum number of classes of a partition of $V$ such that its all classes are $k$-tuple total restrained dominating sets in $G$ we call the $k$-tuple total restrained domatic number of $G$. In this paper, we give some sharp bounds for the $k$-tuple total restrained domination number of a graph, and also calculate it for some of the known graphs. Next, we mainly present basic properties of the $k$-tuple total restrained domatic number of a graph.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
751
763
http://bims.iranjournals.ir/article_529_f5f373afe7aa443a872393ba1dd1ad50.pdf
OD-Characterization of almost simple groups related to $L_{3}(25)$
Gholamreza
Rezaeezadeh
shahrekord university
author
Mohammad Reza
Darafsheh
university of tehran
author
Masoomeh
Sajadi
shahrekord university
author
Masoomeh
Bibak
shahrekord university
author
text
article
2014
eng
Let $G$ be a finite group and $pi(G)$ be the set of all the prime divisors of $|G|$. The prime graph of $G$ is a simple graph $Gamma(G)$ whose vertex set is $pi(G)$ and two distinct vertices $p$ and $q$ are joined by an edge if and only if $G$ has an element of order $pq$, and in this case we will write $psim q$. The degree of $p$ is the number of vertices adjacent to $p$ and is denoted by $deg(p)$. If $|G|=p^{alpha_{1}}_{1}p^{alpha_{2}}_{2}...p^{alpha_{k}}_{k}$, $p_{i}^{,}$s different primes, $p_{1}<p_{2}<...<p_{k}$, then $D(G)=(deg(p_{1}),deg(p_{2}),...,deg(p_{k}))$ is called the degree pattern of $G$. A finite group $G$ is called $k$-fold OD-characterizable if there exist exactly $k$ non-isomorphic groups $S$ with $|G|=|S|$ and $D(G)=D(S)$. In this paper, we characterize groups with the same order and degree pattern as an almost simple groups related to $L_{3}(25)$.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
765
790
http://bims.iranjournals.ir/article_530_c3e97871dde1cadf475decd59146663e.pdf
Asymptotics for the infinite time ruin probability of a dependent risk model with a constant interest rate and dominatedly varying-tailed claim sizes
Kaiyong
Wang
Suzhou University of Science and Technology
author
Fei
Ding
Suzhou University of Science and Technology
author
Hongmei
Wu
Suzhou University of Science and Technology
author
Tingting
Pan
Suzhou University of Science and Technology
author
text
article
2014
eng
This paper mainly considers a nonstandard risk model with a constant interest rate, where both the claim sizes and the inter-arrival times follow some certain dependence structures. When the claim sizes are dominatedly varying-tailed, asymptotics for the infinite time ruin probability of the above dependent risk model have been given.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
40
v.
3
no.
2014
791
807
http://bims.iranjournals.ir/article_531_73c1031a26b7969cd49159a977b0ab99.pdf