eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
293
303
218
Common fixed points of f-weak contractions in cone metric spaces
Wultipol Sintunavarat
poom_teun@hotmail.com
1
Poom Kumam
poom.kum@kmutt.ac.th
2
King Mongkut's University of Technology Thonburi (KMUTT)
King Mongkut's University of Technology Thonburi (KMUTT)
Recently, Choudhury and Metiya [Fixed points of weak contractions in cone metric spaces, Nonlinear Analysis 72 (2010) 1589-1593] proved some fixed point theorems for weak contractions in cone metric spaces. Weak contractions are generalizations of the Banach's contraction mapping, which have been studied by several authors. In this paper, we introduce the notion of $f$-weak contractions and also establish a coincidence and common fixed point result for $f$-weak contractions in cone metric spaces. Our result is supported by an example which include and generalize the results of Choudhury and Metiya's work.
http://bims.iranjournals.ir/article_218_d595625aa45af7f415864e2b1458807a.pdf
Cone metric spaces
Weak contraction
f-weak
contraction
coincidence point
common fixed point
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
305
311
231
Rings with a setwise polynomial-like condition
Ali Tavakoli
ali_tavakoli_targhi@yahoo.com
1
Alireza Abdollahi
a.abdollahi@math.ui.ac.ir
2
Howard E. Bell
hbell@brocku.ca
3
Islamic Azad University - Majlesi Branch
University of Isfahan
Brock University
Let $R$ be an infinite ring. Here we prove that if $0_R$ belongs to ${x_1x_2cdots x_n ;|; x_1,x_2,dots,x_nin X}$ for every infinite subset $X$ of $R$, then $R$ satisfies the polynomial identity $x^n=0$. Also we prove that if $0_R$ belongs to ${x_1x_2cdots x_n-x_{n+1} ;|; x_1,x_2,dots,x_n,x_{n+1}in X}$ for every infinite subset $X$ of $R$, then $x^n=x$ for all $xin R$.
http://bims.iranjournals.ir/article_231_c96d633637c016b61c15d2693daeeffb.pdf
Primitive rings
Polynomial identities
Combinatorial conditions
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
313
322
204
A new family in the stable homotopy groups of spheres
Xiugui Liu
xgliu@nankai.edu.cn
1
Kai Ma
kai-ma@163.com
2
School of Mathematical Sciences and LPMC,
Nankai University,
Tianjin 300071,
P. R China
Mathematics and Information
Science College,Hebei Normal University, 050016,Shijiazhuang, P. R. China
Let $p$ be a prime number greater than three. In this paper, we prove the existence of a new family of homotopy elements in the stable homotopy groups of spheres $pi_{ast}(S)$ which is represented by $h_nh_mtilde{beta}_{s+2}in {rm Ext}_A^{s+4, q[p^n+p^m+(s+2)p+(s+1)]+s}(mathbb{Z}_p,mathbb{Z}_p)$ up to nonzero scalar in the Adams spectral sequence, where $ngeq m+2>5$, $0leq sExt}_A^{s+2,q[(s+2)p+(s+1)]+s}(mathbb{Z}_p,mathbb{Z}_p)$ was defined by X. Wang and Q. Zheng.
http://bims.iranjournals.ir/article_204_3e0a128f7a5b367bd3351fe6549af39e.pdf
stable homotopy groups of spheres
Adams spectral
sequence
May spectral sequence
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
323
331
200
Branches in random recursive k-ary trees
Mehri Javanian
javanian_m@yahoo.com
1
Mohammad Q. Vahidi Asl
m-vahidi@sbu.ac.ir
2
Javanian
Vahidi-Asl
In this paper, using generalized {polya} urn models we find the expected value of the size of a branch in recursive $k$-ary trees. We also find the expectation of the number of nodes of a given outdegree in a branch of such trees.
http://bims.iranjournals.ir/article_200_0fb18b5d341305095aa3c67a34c101b0.pdf
trees
random recursive trees
generalized
P'olya urn models
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
333
347
255
Horvitz-Thompson estimator of population mean under inverse sampling designs
Mohammad Mohammadi
m.mohammadi@sci.ui.ac.ir
1
Mohammad Salehi Marzijarani
salehi_m@cc.iut.ac.ir
2
School of Mathematical Science, Isfahan University of Technology, Isfahan, Iran.
Department of Mathematical Sciences, Isfahan University of Technology 84156-83111, Iran;
Department of Mathematics, Statistics and Physics, Qatar University, P.O.Box 2713, Doha, Qatar.
Inverse sampling design is generally considered to be appropriate technique when the population is divided into two subpopulations, one of which contains only few units. In this paper, we derive the Horvitz-Thompson estimator for the population mean under inverse sampling designs, where subpopulation sizes are known. We then introduce an alternative unbiased estimator, corresponding to post-stratification approach. Both of these are not location-invariant, but this is ignorable for alternative estimator. Using a simulation study, we find that Horvitz-Thompson estimator is an efficient estimator when the mean of the off-interest subpopulation is close to zero while the alternative estimator appears to be an efficient estimator in general.
http://bims.iranjournals.ir/article_255_8bc393a21f635d83fc2a4bdda66f1e39.pdf
Finite Population
Inverse Sampling
Post-stratification
Random Sample Size
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
349
367
211
Comparison results on the preconditioned mixed-type splitting
iterative method for M-matrix linear systems
M. Mohseni Moghadam
mohseni@mail.uk.ac.ir
1
Fatemeh Panjeh Ali Beik
f.beik@vru.ac.ir
2
Shahid Bahonar University of Kerman
Vali-Asr University of Rafsanjan
Consider the linear system Ax=b where the coefficient matrix A is an M-matrix. In the present work, it is proved that the rate of convergence of the Gauss-Seidel method is faster than the mixed-type splitting and AOR (SOR) iterative methods for solving M-matrix linear systems. Furthermore, we improve the rate of convergence of the mixed-type splitting iterative method by applying a preconditioned matrix. Comparison theorems show that the rate of convergence of the preconditioned Gauss-Seidel method is faster than the preconditioned mixed-type splitting and AOR (SOR) iterative methods. Finally, some numerical examples are presented to illustrate the reality of our comparison theorems.
http://bims.iranjournals.ir/article_211_dc5b9e9e1b2a179a471b622100c26a58.pdf
Linear systems
Mixed-type splitting iterative method
Preconditioned matrix
M-matrix
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
369
389
207
An iterative method for amenable semigroup and infinite family of non expansive mappings
in Hilbert spaces
Husain Piri
husain.piri@gmail.com
1
Hamid Vaezi
hvaezi@tabrizu.ac.ir
2
Department of Mathematics, Bonab Higher Education Complex
Faculty of Mathematical Sciences University of Tabriz, Tabriz, Iran
begin{abstract} In this paper, we introduce an iterative method for amenable semigroup of non expansive mappings and infinite family of non expansive mappings in the frame work of Hilbert spaces. We prove the strong convergence of the proposed iterative algorithm to the unique solution of a variational inequality, which is the optimality condition for a minimization problem. The results presented in this paper mainly extend the corresponding results announced by Qin et al. [X. Qin, Y. J. Cho, and S. M. Kang, An iterative method for an infinite family of non-expansive mappings in Hilbert spaces, Bull. Malays. Math. Sci. Soc. 32 (2009) 161-171] and many others. end{abstract}
http://bims.iranjournals.ir/article_207_7d5d8ff16fbbbca2e1790a0f9ab74c87.pdf
common fixed point
strong convergence
Amenable
semigroup
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2011-02-23
38
2
391
401
215
Recurrent metrics in the geometry of second order differential equations
Mircea Crasmareanu
mcrasm@uaic.ro
1
Faculty of Mathematics
University "Al. I. Cuza"
Iasi, 700506
Given a pair (semispray $S$, metric $g$) on a tangent bundle, the family of nonlinear connections $N$ such that $g$ is recurrent with respect to $(S, N)$ with a fixed recurrent factor is determined by using the Obata tensors. In particular, we obtain a characterization for a pair $(N, g)$ to be recurrent as well as for the triple $(S, stackrel{c}{N}, g)$ where $stackrel{c}{N}$ is the canonical nonlinear connection of the semispray $S$. Also, the Weyl connection of conformal gauge theories is obtained as a particular case.
http://bims.iranjournals.ir/article_215_dcd58d4931f7da614e2cbc66aa27cade.pdf
Semispray
nonlinear connection
recurrent metric
Obata operators
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
403
412
407
Projective maximal submodules of extending regular modules
E. Momtahan
1
Yasouj University
We show that a projective maximal submodule of afinitely generated, regular, extending module is a directsummand. Hence, every finitely generated, regular, extendingmodule with projective maximal submodules is semisimple. As aconsequence, we observe that every regular, hereditary, extendingmodule is semisimple. This generalizes and simplifies a result of Dung and Smith. As another consequence, we observe thatevery right continuous ring, whose maximal right ideals areprojective, is semisimple Artinian. This generalizes some resultsof Osofsky and Karamzadeh. We also observe thatfour classes of rings, namely right $aleph_0$-continuous rings,right continuous rings, right $aleph_0$-continuous regular ringsand right continuous regular rings are not axiomatizable.
http://bims.iranjournals.ir/article_407_6a4d7f84d031275eb5d254f9f2871b8d.pdf
continuous rings
extending rings
regular
rings
aleph_0-self-injective rings
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
413
422
208
Finite p-groups with few non-linear irreducible character kernels
Hossein Doostie
doostih@tmu.as.ir
1
Amin Saeidi
saeidi.amin@gmail.com
2
Tarbiat Moallem University
Tarbiat Moallem University
Abstract. In this paper, we classify all of the ﬁnite p-groups with at most three non linear irreducible character kernels.
http://bims.iranjournals.ir/article_208_69f56c704b32022bc49cb06797e62448.pdf
Minimal normal subgroups
few character kernels
strong and weak conditions
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
423
432
212
Invariance of the barycentric subdivision of a simplicial complex
Rashid Zaare-Nahandi
rashidzn@iasbs.ac.ir
1
Institute for Advanced Studies in Basic Sciences
In this paper we prove that a simplicial complex is determined uniquely up to isomorphism by its barycentric subdivision as well as its comparability graph. We also put together several algebraic, combinatorial and topological invariants of simplicial complexes.
http://bims.iranjournals.ir/article_212_de5bc8c7b7b3dc3bfb85ee068f5d21f6.pdf
Simplicial complex
comparability graph
barycentric subdivision
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
433
445
209
On Rickart modules
S Agayev
1
S Halicioglu
halici@ankara.edu.tr
2
A Harmanci
3
Eropean University of Lefke, Cyprus
Department of Mathematics Ankara University
Hacettepe University, Turkey
Let $R$ be an arbitrary ring with identity and $M$ a right $R$-module with $S=$ End$_R(M)$. The module $M$ is called {it Rickart} if for any $fin S$, $r_M(f)=Se$ for some $e^2=ein S$. We prove that some results of principally projective rings and Baer modules can be extended to Rickart modules for this general settings.
http://bims.iranjournals.ir/article_209_a482f3c0119843e2d96bfda7f6af9907.pdf
Rickart modules
Baer modules
reduced
modules
rigid modules
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
447
459
201
Optimal order finite element approximation for a hyperbolic integro-differential equation
Fardin Saedpanah
f_saedpanah@yahoo.com
1
University of Kurdistan,
Department of Mathematics
Semidiscrete finite element approximation of a hyperbolic type integro-differential equation is studied. The model problem is treated as the wave equation which is perturbed with a memory term. Stability estimates are obtained for a slightly more general problem. These, based on energy method, are used to prove optimal order a priori error estimates.
http://bims.iranjournals.ir/article_201_e72a83b9b71c31f92537ef2e58b72810.pdf
finite element method
wave equation
integro-differential equation
Stability
a priori error estimate
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
461
468
198
Properties of multivalent functions associated with certain integral operator
Jin-Lin Liu
jlliu@yzu.edu.cn
1
Department of Mathematics, Yangzhou University
Let A(p) denote the class of functions which are analytic in the open unit disk U. By making use of certain integral operator,we obtain some interesting properties of multivalent analytic functions.
http://bims.iranjournals.ir/article_198_05b363674deba2ef06e6925dc08db279.pdf
Multivalent function
analytic function
integral operator
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
469
477
202
Applications of epi-retractable modules
Bashishth Pandeya
bmpandeya@bhu.ac.in
1
Avanish Chaturvedi
akc99@rediffmail.com
2
Ashok Gupta
ashokg@bhu.ac.in
3
Department of Applied Mathematics, Institute of Technology, Banaras Hindu University,
Varanasi-221005, India.
Department of Mathematics, Jaypee Institute of Information Technology,
(Deemed University) A-10, Sector-62, Noida-201307 (UP), India
Department of Applied Mathematics, Institute of Technology, Banaras Hindu University,
Varanasi-221005, India.
An R-module M is called epi-retractable if every submodule of MR is a homomorphic image of M. It is shown that if R is a right perfect ring, then every projective slightly compressible module MR is epi-retractable. If R is a Noetherian ring, then every epi-retractable right R-module has direct sum of uniform submodules. If endomorphism ring of a module MR is von-Neumann regular, then M is semi-simple if and only if M is epi-retractable. If R is a quasi Frobenius ring, then R is a right hereditary ring if and only if every injective right R-module is semi-simple. A ring R is semi-simple if and only if R is right hereditary and every epiretractable right R-module is projective. Moreover, a ring R is semi-simple if and only if R is a pri and von-Neumann regular.
http://bims.iranjournals.ir/article_202_388757ddee7a3a67ab050c9a998e2049.pdf
Epi-retractable modules
semi-simple rings
Perfect rings
Hereditary rings
von-Numann regular rings
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
479
490
203
Some vector fields on a riemannian manifold with semi-symmetric metric connection
Füsun Özen Zengin
fozen@itu.edu.tr
1
Sezgin Altay Demirbag
saltay@itu.edu.tr
2
S. Aynur Uysal
auysal@dogus.edu.tr
3
Hülya Bagdatli Yilmaz
hbagdatli@marmara.edu.tr
4
Istanbul Technical University
Istanbul Technical University
Dogus University
Marmara University
In the first part of this paper, some theorems are given for a Riemannian manifold with semi-symmetric metric connection. In the second part of it, some special vector fields, for example, torse-forming vector fields, recurrent vector fields and concurrent vector fields are examined in this manifold. We obtain some properties of this manifold having the vectors mentioned above.
http://bims.iranjournals.ir/article_203_231ecca82cd01017b92531f34000f4d6.pdf
Semi-symmetric metric connection
sectional curvature
conformally flat manifold
pseudo symmetric manifold
concircular
vector field
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
491
506
205
Riordan group approaches in matrix factorizations
Emrah Kilic
ekilic@etu.edu.tr
1
Nese Omur
neseomur@kocaeli.edu.tr
2
Gulfer Tatar
gulfera@kocaeli.edu.tr
3
TOBB University of Economics and Technology Mathematics Department
Kocaeli University Mathematics Department
Kocaeli University Mathematics Department
In this paper, we consider an arbitrary binary polynomial sequence {A_n} and then give a lower triangular matrix representation of this sequence. As main result, we obtain a factorization of the innite generalized Pascal matrix in terms of this new matrix, using a Riordan group approach. Further some interesting results and applications are derived.
http://bims.iranjournals.ir/article_205_da5f4f10d7f10a4b73c7db3f21ccb967.pdf
Riordan Group
Factorization
Binary Recurrences
Pascal Matrix
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
507
515
210
Some homological properties of amalgamated duplication of a ring along an ideal
Mohamed Chhiti
chhiti.med@hotmail.com
1
Najib Mahdou
mahdou@hotmail.com
2
University of Fez, Fez, Morocco
Department of Mathematics, Faculty of Sciences and Technology, University of Fez, Fez, Morocco.
In this work, we investigate the transfer of some homological properties from a ring $R$ to its amalgamated duplication along some ideal $I$ of $R$ $Rbowtie I$, and then generate new and original families of rings with these properties.
http://bims.iranjournals.ir/article_210_485789e3f153661d4d8c1136c73cb0d1.pdf
Amalgamated
Perfect ring
(n
d)-ring
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
517
528
214
A note on the socle of certain types of f-rings
Themba Dube
tdube2013@yahoo.co.za
1
University of South Africa
For any reduced commutative $f$-ring with identity and bounded inversion, we show that a condition which is obviously necessary for the socle of the ring to coincide with the socle of its bounded part, is actually also sufficient. The condition is that every minimal ideal of the ring consist entirely of bounded elements. It is not too stringent, and is satisfied, for instance, by rings of continuous functions.
http://bims.iranjournals.ir/article_214_3c1783bf3988903f43f20700e3e575bc.pdf
frame
function rings
ideal
socle
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2012-07-15
38
2
529
542
217
Ring structures of mod p equivariant cohomology rings and ring homomorphisms between them
Yanchang Chen
cyc810707@163.com
1
Yanying Wang
wyanying2003@yahoo.com.cn
2
College of Mathematics and Information Science, Hebei Normal University, Yuhua
Road 113, Shijiazhuang 050016, P. R. China
College of Mathematics and Information Science, Hebei Normal University, Yuhua Road 113, Shijiazhuang 050016, P. R. China
In this paper, we consider a class of connected oriented (with respect to Z/p) closed G-manifolds with a non-empty finite fixed point set, each of which is G-equivariantly formal, where G = Z/p and p is an odd prime. Using localization theorem and equivariant index, we give an explicit description of the mod p equivariant cohomology ring of such a G-manifold in terms of algebra. This makes it possible to determine the number of equivariant cohomology rings (up to isomorphism) of such 2-dimensional G-manifolds. Moreover, we obtain a description of the ring homomorphism between equivariant cohomology rings of such two G-manifolds induced by a G-equivariant map, and show a characterization of the ring homomorphism.
http://bims.iranjournals.ir/article_217_d78bd5727580f199e3b327f8189d5d8a.pdf
G-manifold
equivariant index
equivariant cohomology
ring homomorphism