Ferdowsi University of Mashhad
Iranian Journal of Numerical Analysis and Optimization
2423-6977
2423-6969
1
1
2008
01
01
On algebraic characterizations for finiteness of the dimension of EG
1
22
EN
Olympia
Talelli
Department of Mathematics, University of Athens
Panepistemiopolis, 15784 Athens - Greece
otalelli@cc.uoa.gr
10.22067/ijnao.v1i1.616
Certain algebraic invariants of the integral group ring ZG of a group G were introduced and investigated in relation to the problem of extending the Farrell-Tate cohomology, which is defined for the class of groups of finite virtual cohomological dimension. It turns out that the finiteness of these invariants of a group G implies the existence of a generalized Farrell-Tate cohomology for G which is computed via complete resolutions. In this article we present these algebraic invariants and their basic properties and discuss their relationship to the generalized Farrell-Tate cohomology. In addition we present the status of conjecture which claims that the finiteness of these invariants of a group G is equivalent to the existence of a finite dimensional model for EG, the classifying space for proper actions.
Farrell-Tate cohomology,virtual cohomological dimension,complete resolution,finitistic dimension of the integral group ring,classifying space for proper action
https://ijnao.um.ac.ir/article_24399.html
https://ijnao.um.ac.ir/article_24399_5a1d6a9475aef57c33c2f263325f84df.pdf
Ferdowsi University of Mashhad
Iranian Journal of Numerical Analysis and Optimization
2423-6977
2423-6969
1
1
2008
01
01
New classes of infinite groups
23
40
EN
V.I.
Senashov
Institute of Computational Modeling of Siberian Division of Russian Academy of Sciences
sen@icm.krasn.ru
V.P.
Shunkov
Institute of Computational Modeling of Siberian Division of Russian Academy of Sciences
10.22067/ijnao.v1i1.617
In this article, we consider some new classes of groups, namely, Mp-groups, T0-groups,Ø-groups,Ø0-groups, groups with finitely embedded involution, which were appeared at the end of twenties century. These classes of infinite groups with finiteness conditions were introduced by V.P. Shunkov. We give some review of new results on these classes of groups.
Ø-groups,involution,Frobenius group,Chernikov groups,quasi cyclic groups
https://ijnao.um.ac.ir/article_24400.html
https://ijnao.um.ac.ir/article_24400_30fee98eaa7afc4be4ec3fa477ae082a.pdf
Ferdowsi University of Mashhad
Iranian Journal of Numerical Analysis and Optimization
2423-6977
2423-6969
1
1
2008
01
01
Groups with soluble minimax conjugate classes of subgroups
41
50
EN
Francesco
Russo
Mathematics Department, University of Wuerzburg, Wuerzburg, Germany
francesco.russo@dma.unina.it
10.22067/ijnao.v1i1.618
A classical result of Neumann characterizes the groups in which each subgroup has finitely many conjugates only as central-by-finite groups. If X is a class of groups, a group G is said to have X-conjugate classes of subgroups if G/coreG(NG(H)) 2 X for each subgroup H of G. Here we study groups which have soluble minimax conjugate classes of subgroups, giving a description in terms of G/Z(G). We also characterize FC-groups which have soluble minimax conjugate classes of subgroups.
Conjugacy classes,soluble minimax groups,FC-groups,polycyclic groups
https://ijnao.um.ac.ir/article_24401.html
https://ijnao.um.ac.ir/article_24401_6df15ff724c0ef55fd1ece0d41224349.pdf
Ferdowsi University of Mashhad
Iranian Journal of Numerical Analysis and Optimization
2423-6977
2423-6969
1
1
2008
01
01
A numerical solution for an inverse heat conduction problem
51
58
EN
Abdollah
Shidfar
Department of Mathematics, Iran University of Science and Technology
Narmak, Tehran-16, Iran
shidfar@iust.ac.ir
Ali
Zakeri
Faculty of Science, K.N. Toosi University of Technology, Tehran, Iran
azakeri@kntu.ac.ir
10.22067/ijnao.v1i1.619
In this paper, we demonstrate the existence and uniqueness a semianalytical solution of an inverse heat conduction problem (IHCP) in the form: ut = uxx in the domain D = {(x, t)| 0 < x < 1, 0 < t T}, u(x, T) = f(x), u(0, t) = g(t), and ux(0, t) = p(t), for any 0 t T. Some numerical experiments are given in the final section.
Inverse heat conduction problem,semi-analytical solution,finite difference method
https://ijnao.um.ac.ir/article_24402.html
https://ijnao.um.ac.ir/article_24402_d097ae55c225708c78265c9110687ab4.pdf
Ferdowsi University of Mashhad
Iranian Journal of Numerical Analysis and Optimization
2423-6977
2423-6969
1
1
2008
01
01
Uniformly continuous 1-1 functions on ordered fields not mapping interior to interior
59
65
EN
Mojtaba
Moniri
Department of Mathematics,
Tarbiat Modarres University, Tehran
mojmon@ipm.ir
Jafar
S. Eivazloo
Department of Mathematics,
Tarbiat Modarres University, Tehran
10.22067/ijnao.v1i1.620
In an earlier work we showed that for ordered fields F not isomorphic to the reals R, there are continuous 1-1 unctions on [0, 1]F which map some interior point to a boundary point of the image (and so are not open). Here we show that over closed bounded intervals in the rationals Q as well as in all non-Archimedean ordered fields of countable cofinality, there are uniformly continuous 1-1 functions not mapping interior to interior. In particular, the minimal non-Archimedean ordered field Q(x), as well as ordered Laurent series fields with coefficients in an ordered field accommodate such pathological functions.
Ordered field,gap,monotone complete,open map
https://ijnao.um.ac.ir/article_24403.html
https://ijnao.um.ac.ir/article_24403_8abeb41e6281cf2da34670698078b0af.pdf
Ferdowsi University of Mashhad
Iranian Journal of Numerical Analysis and Optimization
2423-6977
2423-6969
1
1
2008
01
01
Statistical inference based on k-records
67
82
EN
J.
Ahmadi
Department of Statistics, Ferdowsi University of Mashhad, Mashhad
ahmadi-j@um.ac.ir
M.
Doostparast
Department of Statistics, Ferdowsi University of Mashhad, Mashhad
doostparast@wali.um.ac.ir
10.22067/ijnao.v1i1.621
In this paper, an extension of record models, well known as k-records, is considered. Bayesian estimation as well as prediction based on k-records are presented when the underlying distribution is assumed to have a general form. The proposed procedure is applied to the Exponential, Weibull and Pareto models in one parameter case. Also, the two-parameter Exponential distribution, when both parameters are unknown, is studied in more details. Since the ordinary record values are contained in the k-records, by putting k = 1, the results for usual records can be obtained as special case.
Admissibility,Bayes prediction,Bayesian estimation,conjugate prior,weibull distribution
https://ijnao.um.ac.ir/article_24404.html
https://ijnao.um.ac.ir/article_24404_49e7a80b32455eeb6a7cee7719987b78.pdf
Ferdowsi University of Mashhad
Iranian Journal of Numerical Analysis and Optimization
2423-6977
2423-6969
1
1
2008
01
01
Shrinkage estimation of the regression parameters with multivariate normal errors
83
100
EN
M.
Arashi
Department of Statistics, Ferdowsi University of Mashhad, Mashhad
m_arashi_stat@yahoo.com
S. M. M.
Tabatabaey
Department of Statistics, Ferdowsi University of Mashhad, Mashhad
tabatabaey@yahoo.com
10.22067/ijnao.v1i1.622
In the linear model y=XB+e with the errors distributed as normal, we obtain generalized least square (GLS), restricted GLS (RGLS), preliminary test (PT), Stein-type shrinkage (S) and positive-rule shrinkage (PRS) estimators for regression vector parameter \beta when the covariance structure in known. We compare the quadratic risks of the underlying estimators and propose the dominance orders of the five estimators.
GLS estimator,preliminary test estimator,stein-type shrinkage estimator,positive-rule shrinkage estimator
https://ijnao.um.ac.ir/article_24405.html
https://ijnao.um.ac.ir/article_24405_abdacfca87e72c9cfe6603b793285074.pdf