Recursos de colección
Project Euclid (Hosted at Cornell University Library) (192.320 recursos)
Nihonkai Mathematical Journal
Nihonkai Mathematical Journal
Saito, Yutaka; Tanaka, Tamaki
In the paper, we propose Ricceri type theorem on Fan-Takahashi minimax inequality
for set-valued maps by using the scalarization method proposed by Kuwano, Tanaka
and Yamada based on a certain type of the set-relations.
Riva, Matteo Dalla; Takahasi, Sin-Ei
Given a non-trivial automorphism (resp. anti-automorphism) of a semigroup, we
study its homomorphic (resp. anti-homomorphic) extensions to a larger semigroup
by considering the images of the absorbing elements. Then we exhibit some
examples to show the application of the results obtained.
Hatori, Osamu
Let $S_n$ be the unit sphere with respect to the operator norm of the algebra of
$n\times n$ complex matrices. We give a complete description of the form of
surjections on $S_n$ which preserve the metric induced by a unitarily invariant
strictly convex norm.
Konno, Kazuhiro
Multiple fibers of the simplest kind in a pencil of algebraic curves are studied,
in order to clarify the influence on the gonality and the base locus of the
canonical linear system.
Murakami, Satomi; Ohwa, Hiroki
The purpose of this paper is to investigate periodic points of discontinuous
maps. For some discontinuous maps, we establish a characterization of periodic
points.
Hatori, Osamu
We give a condition on commutativity of a pair of normal operators with respect to the continuous functional calculus. We show a generalization of the theorem of Fuglede and Putnum with respect to the continuous functional calculus.
Izumida, Tamotsu
In this paper, we consider a generalized triangle inequality of the following
type: \begin{equation*} \Vert a_1 x_1+\cdots + a_1 x_n \Vert ^p \leq \Vert
x_1\Vert^p +\cdots +\Vert x_n\Vert ^p \ (x_1,\ldots, x_n \in X ),
\end{equation*} where $(X, \Vert \cdot \Vert)$ is a normed space, $(a_1, \ldots,
a_n) \in \Bbb C^n$ and $p>0$. By using generalized $\ell_p$-spaces, we present a
characterization of above inequality for infinite sequences
$\{x_n\}_{n=1}^{\infty} \subset X$.
Banerjee, Abhijit
Dragomir, Silvestru Sever
Some new inequalities for the functional
\begin{align*}
& E_{T}\left( f,u\right) \\
& :=f\left( b\right) \left( u\left( b\right) -\frac{1}{b-a}%
\int_{a}^{b}u\left( t\right) dt\right) +f\left( a\right) \left( \frac{1}{b-a}%
\int_{a}^{b}u\left( t\right) dt-u\left( a\right) \right) \\
& -\int_{a}^{b}f\left( t\right) du\left( t\right) ,
\end{align*}
under various assumptions for the functions $f$ and $u$ are given.
Applications for functions of selfadjoint operators and unitary operators on
complex Hilbert spaces are also provided.
Goto, Satoru; Komatsu, Kazushi; Yagi, Jun
We provide a mathematical model of $n$-membered straight-chain
hydrocarbon molecules.
The configuration space of the model is parametrized by chain lengths.
By assuming the bond angle conditions required for hydrocarbon molecules,
we determine the topological types of fibers of the configuration space of the model by chain lengths when $n = 5$.
Nakazi, Tarahiko
Let $M$ be a shift invariant subspace in the two variable Hardy space
$H^2(\Gamma_z\times\Gamma_w)$. We study $\mathcal{M}(M_z)=\{\phi\in
H^\infty(\Gamma_z\times \Gamma_w) : \phi M_z\subseteq M_z\}$ where $M_z=M\ominus
zM$. We give several sufficient conditions for
$\mathcal{M}(M_z)=H^\infty(\Gamma_w)$ where $H^\infty(\Gamma_w)$ is the one
variable Hardy space.
Seto, Michio; Suda, Sho; Taniguchi, Tetsuji
We study graph homomorphisms over finite graphs from a viewpoint of reproducing
kernel Hilbert space theory. In particular, introducing de Branges-Rovnyak
theory into graph theory, the relation between injective graph homomorphisms and
de Branges-Rovnyak spaces is discussed in detail.
Suzuki, Naoyha
On the basis of Dupont's work, we exhibit a cocycle in the simplicial de Rham
complex which represents the Chern character. We also prove the related
conjecture due to Brylinski. This gives a way to construct a cocycle in a local
truncated complex.
Mizuguchi, Hiroyasu
Recently, the author and two other researchers
constructed a calculation method for the Dunkl-Williams constant $DW(X)$ of
a normed linear space $X$.
Using the method, we determined the constant of $\mathbb{R}^2$ with symmetric octagonal norms.
In this paper, we calculate the Dunkl-Williams constant of its dual space.
As the result, the space $\mathbb{R}^2$ with symmetric octagonal norm becomes an example
for which the Dunkl-Williams constant of the own space and the dual space have same value.
Nogawa, Tatsuya
In this paper we show that the extension of a surjective isometry on the unit
sphere in a normed linear space is unique.
Hojo, Mayumi; Takahashi, Wataru
Generalized split feasibility problem governed by a widely more generalized
hybrid mapping is studied. In particular, strong convergence of this algorithm
is proved. As tools, resolvents of maximal monotone operators are technically
maneuvered to facilitate the argument of the proof to the main result.
Applications to iteration methods for various nonlinear mappings and to
equilibrium problem are included.
Taniyama, Kouki
Let $X$ be a topological space and $f:X\to X$ a bijection. Let ${\mathcal
C}(X,f)$ be a set of integers such that an integer $n$ is an element of
${\mathcal C}(X,f)$ if and only if the bijection $f^n:X\to X$ is continuous. A
subset $S$ of the set of integers ${\mathbb Z}$ is said to be realizable if
there is a topological space $X$ and a bijection $f:X\to X$ such that
$S={\mathcal C}(X,f)$. A subset $S$ of ${\mathbb Z}$ containing $0$ is called a
submonoid of ${\mathbb Z}$ if the sum of any two elements of $S$ is also an
element of $S$. We show that a subset $S$...
Kojima, Hideo
Normal del Pezzo surfaces of rank one with only rational log canonical
singularities are studied. We classify such surfaces with unique singular
points. Moreover, by using the classification result and the results in [11], we
study the fundamental groups of their smooth parts.
Sarikaya, Mehmet Zeki; Yaldiz, Hatice
In this paper, some generalization integral inequalities of Hermite-Hadamard type
for functions whose derivatives are convex in modulus are given by using
fractional integrals.
Hosokawa, Takuya; Seto, Michio
We discuss linear equations whose coefficients are bounded composition operators
on the Hardy space over the unit disk. Some connections between those equations,
Pick interpolation and de Branges-Rovnyak spaces are studied in detail.