en
jalali
1390
8
1
gregorian
2011
11
1
6
2
online
1
fulltext
en
On the Decomposition of Hilbert Spaces
Basic relation between numerical range and Davis-Wielandt shell of an operator $A$ acting on a Hilbert space with orthonormal basis $xi={e_{i}|i in I}$ and its conjugate $bar{A}$ which is introduced in this paper are obtained. The results are used to study the relation between point spectrum, approximate spectrum and residual spectrum of $A$ and $bar{A}$. A necessary and sufficient condition for $A$ to be self-conjugate ($A=bar{A}$) is given using a subgroup of H.
Numerical range, Davis-Wielandt shell, Spectra, Conjugate of an operator.
1
7
http://ijmsi.ir/browse.php?a_code=A-10-1-94&slc_lang=en&sid=1
H.R.
Afshin
`0031947532846002168`

0031947532846002168
Yes
M.A.
Ranjbar
`0031947532846002169`

0031947532846002169
No
en
Properties of Central Symmetric X-Form Matrices
In this paper we introduce a special form of symmetric matrices that is called central symmetric $X$-form matrix and study some properties, the inverse eigenvalue problem and inverse singular value problem for these matrices.
Inverse eigenvalue problem, Inverse singular value problem, eigenvalue, singular value.
9
20
http://ijmsi.ir/browse.php?a_code=A-10-1-95&slc_lang=en&sid=1
A.M.
Nazari
`0031947532846002172`

0031947532846002172
Yes
E.
Afshari
`0031947532846002173`

0031947532846002173
No
A.
Omidi Bidgoli
`0031947532846002174`

0031947532846002174
No
en
Shift Invariant Spaces and Shift Preserving Operators on Locally Compact Abelian Groups
We investigate shift invariant subspaces of $L^2(G)$, where $G$ is a locally compact abelian group. We show that every shift invariant space can be decomposed as an orthogonal sum of spaces each of which is generated by a single function whose shifts form a Parseval frame. For a second countable locally compact abelian group $G$ we prove a useful Hilbert space isomorphism, introduce range functions and give a characterization of shift invariant subspaces of $L^2(G)$ in terms of range functions. Finally, we investigate shift preserving operators on locally compact abelian groups. We show that there is a one-to-one correspondence between shift preserving operators and range operators on $L^2(G)$ where $G$ is a locally compact abelian group.
locally compact abelian group, shift invariant space, frame, range function, shift preserving operator, range operator.
21
32
http://ijmsi.ir/browse.php?a_code=A-10-1-96&slc_lang=en&sid=1
R.
Raisi Tousi
`0031947532846002170`

0031947532846002170
Yes
R.A.
Kamyabi Gol
`0031947532846002171`

0031947532846002171
No
en
Deformation of Outer Representations of Galois Group II
This paper is devoted to deformation theory of "anabelian" representations of the absolute Galois group landing in outer automorphism group of the algebraic fundamental group of a hyperbolic smooth curve defined over a number-field. In the first part of this paper, we obtained several universal deformations for Lie-algebra versions of the above representation using the Schlessinger criteria for functors on Artin local rings. In the second part, we use a version of Schlessinger criteria for functors on the Artinian category of nilpotent Lie algebras which is formulated by Pridham, and explore arithmetic applications.
Deformation theory, Artin local rings, Schlessinger criteria.
33
41
http://ijmsi.ir/browse.php?a_code=A-10-1-97&slc_lang=en&sid=1
Arash
Rastegar
`0031947532846002175`

0031947532846002175
Yes
en
Linear Preservers of Majorization
For vectors $X, Yin mathbb{R}^{n}$, we say $X$ is left matrix majorized by $Y$ and write $X prec_{ell} Y$ if for some row stochastic matrix $R, ~X=RY.$ Also, we write $Xsim_{ell}Y,$ when $Xprec_{ell}Yprec_{ell}X.$ A linear operator $Tcolon mathbb{R}^{p}to mathbb{R}^{n}$ is said to be a linear preserver of a given relation $prec$ if $Xprec Y$ on $mathbb{R}^{p}$ implies that $TXprec TY$ on $mathbb{R}^{n}$. In this note we study linear preservers of $sim_{ell}$ from $mathbb{R}^{p}$ to $mathbb{R}^{n}.$ In particular, we characterize all linear preservers of $sim_{ell}$ from $mathbb{R}^{2}$ to $mathbb{R}^{n},$ and also, all linear preservers of $sim_{ell}$ from $mathbb{R}^{p}$ to $mathbb{R}^{p}.$
Linear preservers, Row stochastic matrix, Matrix majorization.
43
50
http://ijmsi.ir/browse.php?a_code=A-10-1-98&slc_lang=en&sid=1
Fatemeh
Khalooei
`0031947532846002176`

0031947532846002176
Yes
Abbas
Salemi
`0031947532846002177`

0031947532846002177
No
en
On Schur Multipliers of Pairs and Triples of Groups with Topological Approach
In this paper, using a relation between Schur multipliers of pairs and triples of groups, the fundamental group and homology groups of a homotopy pushout of Eilenberg-MacLane spaces, we present among other things some behaviors of Schur multipliers of pairs and triples with respect to free, amalgamated free, and direct products and also direct limits of groups with topological approach.
Schur multiplier of a pair of groups, Schur multiplier of a triple of groups, Homology group, Homotopy group, Eilenberg-MacLane space, Homotopy pushout.
51
65
http://ijmsi.ir/browse.php?a_code=A-10-1-99&slc_lang=en&sid=1
Hanieh
Mirebrahimi
`0031947532846002180`

0031947532846002180
Yes
Behrooz
Mashayekhy
`0031947532846002181`

0031947532846002181
No
en
The Hyper-Wiener Polynomial of Graphs
The distance $d(u,v)$ between two vertices $u$ and $v$ of a graph $G$ is equal to the length of a shortest path that connects $u$ and $v$. Define $WW(G,x) = 1/2sum_{{ a,b } subseteq V(G)}x^{d(a,b) + d^2(a,b)}$, where $d(G)$ is the greatest distance between any two vertices. In this paper the hyper-Wiener polynomials of the Cartesian product, composition, join and disjunction of graphs are computed.
Hyper-Wiener polynomial, graph operation.
67
74
http://ijmsi.ir/browse.php?a_code=A-10-1-100&slc_lang=en&sid=1
G.H.
Fath-Tabar
`0031947532846002178`

0031947532846002178
Yes
A.R.
Ashrafi
`0031947532846002179`

0031947532846002179
No
en
A Study of the Total Graph
Let R be a commutative ring with $Z(R)$ its set of zero-divisors. In this paper, we study the total graph of $R$, denoted by $T(Gamma(R))$. It is the (undirected) graph with all elements of R as vertices, and for distinct $x, yin R$, the vertices $x$ and $y$ are adjacent if and only if $x + yinZ(R)$. We study the chromatic number and edge connectivity of this graph.
Zero-divisor graph, Total graph.
75
80
http://ijmsi.ir/browse.php?a_code=A-10-1-101&slc_lang=en&sid=1
Abolfazl
Tehranian
`0031947532846002182`

0031947532846002182
Yes
Hamid Reza
Maimani
`0031947532846002183`

0031947532846002183
No