Let $G$ be an automorphism group of a $2$-$(v,k,4)$ symmetric design $\mathcal D$. In this paper, we prove that if $G$ is flag-transitive point-primitive, then the socle of $G$ cannot be an exceptional group of Lie type.
There are many long-standing conjectures related with some labellings of trees. It is important to connect labellings that are related with conjectures. We find some connections between known labellings of simple graphs.
Let $X$, $Y$ and $Z$ be Banach spaces and $f:X\times Y \longrightarrow Z$ a bounded bilinear map. In this paper we study the relation between Arens regularity of $f$ and the reflexivity of $Y$. We also give some conditions under which the Arens regularity of a Banach algebra $A$ implies the Arens regularity of certain Banach right module action of $A$ .
In this paper we introduce continuous $g$-Bessel multipliers in Hilbert spaces and investigate some of their properties. We provide some conditions under which a continuous $g$-Bessel multiplier is a compact operator. Also, we show the continuous dependency of continuous $g$-Bessel multipliers on their parameters.
In this paper we apply hybrid functions of general block-pulse functions and Legendre polynomials for solving linear and nonlinear multi-order fractional differential equations (FDEs). Our approach is based on incorporating operational matrices of FDEs with hybrid functions that reduces the FDEs problems to the solution of algebraic systems. Error estimate that verifies a convergence of the approximate solutions is considered. The numerical results obtained by this scheme have been compared with the exact solution to show the efficiency of the method.
For a graph $G$, let $P(G,lambda)$ denote the chromatic polynomial of $G$. Two graphs $G$ and $H$ are chromatically equivalent if they share the same chromatic polynomial. A graph $G$ is chromatically unique if any graph chromatically equivalent to $G$ is isomorphic to $G$. A $K_4$-homeomorph is a subdivision of the complete graph $K_4$. In this paper, we determine a family of chromatically unique $K_4$-homeomorphs which have girth 9 and has exactly one path of length 1, and give sufficient and necessary condition for the graphs in this family to be chromatically unique.
Based on a definition for circle in Finsler space, recently proposed by one of the present authors and Z. Shen, a natural definition of extrinsic sphere in Finsler geometry is given and it is shown that a connected submanifold of a Finsler manifold is totally umbilical and has non-zero parallel mean curvature vector field, if and only if its circles coincide with circles of the ambient manifold. Finally, some examples of extrinsic sphere in Finsler geometry, particularly in Randers spaces are given.
Our contribution in this paper is to propose an iterative algorithm which does not require prior knowledge of operator norm and prove a strong convergence theorem for approximating a solution of split equality fixed point problem for quasi-nonexpansive mappings in a real Hilbert space. So many have used algorithms involving the operator norm for solving split equality fixed point problem, but as widely known the computation of these algorithms may be difficult and for this reason, some researchers have recently started constructing iterative algorithms with a way of selecting the step-sizes such that the implementation of the algorithm does not require the calculation or estimation of the operator norm. To the best of our knowledge most of the works in literature that do not involve the calculation or estimation of the operator norm only obtained weak convergence results. In this paper, by appropriately modifying the simultaneous iterative algorithm introduced by Zhao, we state and prove a strong convergence result for solving split equality problem. We present some applications of our result and then give some numerical example to study its efficiency and implementation at the end of the paper.
In this paper, we consider the multipoint boundary value problem for one-dimensional $p$-Laplacian dynamic equation on time scales. We prove the existence at least three positive solutions of the boundary value problem by using the Avery and Peterson fixed point theorem. The interesting point is that the non-linear term $f$ involves a first-order derivative explicitly. Our results are new for the special cases of difference equations and differential equations as well as in the general time scale setting.
In this paper, we consider a new study about fractional $\Delta$-difference equations. We consider two special classes of Sturm-Liouville problems equipped with fractional $\Delta$-difference operators. In couple of steps, the Lyapunov type inequalities for both classes will be obtained. As application, some qualitative behaviour of mentioned fractional problems such as stability, spectral, disconjugacy and some interesting results about zeros of (oscillatory) solutions will be concluded.
In this paper, we shall establish some extended Simpson-type inequalities for differentiable convex functions and differentiable concave functions which are connected with Hermite-Hadamard inequality. Some error estimates for the midpoint, trapezoidal and Simpson formula are also given.
Let $\mathcal{A}$ be a unital Banach algebra, $\mathcal{M}$ be a left $\mathcal{A}$-module, and $W$ in $\mathcal{Z}(\mathcal{A})$ be a left separating point of $\mathcal{M}$. We show that if $\mathcal{M}$ is a unital left $\mathcal{A}$-module and $\delta$ is a linear mapping from $\mathcal{A}$ into $\mathcal{M}$, then the following four conditions are equivalent: (i) $\delta$ is a Jordan left derivation; (ii)$\delta$ is left derivable at $W$; (iii) $\delta$ is Jordan left derivable at $W$; (iv)$A\delta(B)+B\delta(A)=\delta(W)$ for each $A,B$ in $\mathcal{A}$ with $AB=BA=W$. Let $\mathcal{A}$ have property ($\mathbb{B}$) (see Definition \ref{Prop_B}), $\mathcal{M}$ be a Banach left $\mathcal{A}$-module, and $\delta$ be a continuous linear operator from $\mathcal{A}$ into $\mathcal{M}$. Then $\delta$ is a generalized Jordan left derivation if and only if $\delta$ is Jordan left derivable at zero. In addition, if there exists an element $C\in\mathcal{Z}(\mathcal{A})$ which is a left separating point of $\mathcal{M}$, and $Rann_{\mathcal{M}}(\mathcal{A})=\{0\}$, then $\delta$ is a generalized left derivation if and only if $\delta$ is left derivable at zero.
The Steiner distance of a graph, introduced by Chartrand, Oellermann, Tian and Zou in 1989, is a natural generalization of the concept of classical graph distance. For a connected graph $G$ of order at least $2$ and $S\subseteq V(G)$, the Steiner distance $d(S)$ among the vertices of $S$ is the minimum size among all connected subgraphs whose vertex sets contain $S$. Let $n,k$ be two integers with $2\leq k\leq n$. Then the Steiner $k$-eccentricity $e_k(v)$ of a vertex $v$ of $G$ is defined by $e_k(v)=\max \{d(S)\,|\,S\subseteq V(G), |S|=k, and v\in S\}$. Furthermore, the Steiner $k$-diameter of $G$ is $sdiam_k(G)=\max \{e_k(v)\,| v\in V(G)\}$. In 2011, Chartrand, Okamoto and Zhang showed that $k-1\leq sdiam_k(G)\leq n-1$. In this paper, graphs with $sdiam_3(G)=2,3,n-1$ are characterized, respectively. We also consider the Nordhaus-Gaddum-type results for the parameter $sdiam_k(G)$. We determine sharp upper and lower bounds of $sdiam_k(G)+sdiam_k(\overline{G})$ and $sdiam_k(G)\cdot sdiam_k(\overline{G})$ for a graph $G$ of order $n$. Some graph classes attaining these bounds are also given.
We first study some properties of $A$-module homomorphisms $\theta:X\rightarrow Y$, where $X$ and $Y$ are Fréchet $A$-modules and $A$ is a unital Fréchet algebra. Then we show that if there exists a continued bisection of the identity for $A$, then $\theta$ is automatically continuous under certain condition on $X$. In particular, every homomorphism from $A$ into certain Fréchet algebras (including Banach algebra) is automatically continuous. Finally, we show that every unital Fréchet algebra with a continued bisection of the identity, is functionally continuous.
In this article we consider the sequences of sample and population covariance operators for a sequence of arrays of Hilbertian random elements. Then under the assumptions that sequences of the covariance operators norm are uniformly bounded and the sequences of the principal component scores are uniformly sumable, we prove that the convergence of the sequences of covariance operators would imply the convergence of the corresponding sequences of the sample andpopulation eigenvalues and eigenvectors, and vice versa. In particular we prove that the principal component scores converge in distribution in certain family of Hilbertian elliptically contoured distributions.
The aim of this paper is to compute a simplicial cohomology group of some specific digital images. Then we define ringand algebra structures of a digital cohomology with the cup product. Finally, we prove a special case of the Borsuk-Ulam theorem fordigital images.
In this paper, it is proved that all simple $K_4$-groups of type $L_2(q)$ can be characterized by their maximum element orders together with their orders. Furthermore, the automorphism groups of simple $K_4$-groups of type $L_2(q)$ are also considered.
At present paper, we establish the existence of pullback $\mathcal{D}$-attractor for the process associated with non-autonomous partly dissipative reaction-diffusion equation in $L^2(\mathbb{R}^n)\times L^2(\mathbb{R}^n)$. In order to do this, by energy equation method we show that the process, which possesses a pullback $\mathcal{D}$-absorbing set, is pullback $\widehat{D}_0$-asymptotically compact.
In this paper, operational matrices of Riemann-Liouville fractional integration and Caputo fractional differentiation for shifted Jacobi polynomials are considered. Using the given initial conditions, we transform the fractional differential equation (FDE) into a modified fractional differential equation with zero initial conditions. Next, all the existing functions in modified differential equation are approximated by shifted Jacobi polynomials. Then, operational matrices and spectral collocation method are applied to obtain a linear or nonlinear system of algebraic equations. System of algebraic equations can be simultaneously solved (e.g. using Mathematica^{TM}). Main characteristic behind of the this technique is that only a small number of shifted Jacobi polynomials is needed to obtain a satisfactory result which demonstrates the validity and efficiency of the method. Comparison between this method and some other methods confirm the good performance of the presented method. Also, this method is generalized for the multi-point fractional differential equation.
In this article, we discuss measure theoretic characterizations for weighted composition operators in some operator classes on $L^{2}(\Sigma)$ such as, $n$-power normal, $n$-power quasi-normal, $k$-quasi-paranormal and quasi-class$A$. Then we show that weighted composition operators can separate these classes.