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BKMS
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2022-03-31
Duadic codes over finite local rings
Arezoo Soufi Karbaski, Karim SameiAbstract : In this paper, we introduce duadic codes over finite local rings and concentrate on quadratic residue codes. We study their properties and give the comprehensive method for the computing the unique idempotent generator of quadratic residue codes.
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2022-03-31
Characterizations of Jordan derivable mappings at the unit element
Jiankui Li, Shan Li, Kaijia LuoAbstract : Let $\mathcal{A}$ be a unital Banach algebra, $\mathcal{M}$ a unital $\mathcal{A}$-bimodule, and $\delta$ a linear mapping from $\mathcal{A}$ into $\mathcal{M}$. We prove that if $\delta$ satisfies $\delta(A)A^{-1}+A^{-1}\delta(A)+A\delta(A^{-1})+\delta(A^{-1})A=0$ for every invertible element $A$ in $\mathcal{A}$, then $\delta$ is a Jordan derivation. Moreover, we show that $\delta$ is a Jordan derivable mapping at the unit element if and only if $\delta$ is a Jordan derivation. As an application, we answer the question posed in \cite[Problem 2.6]{E}.
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2022-03-31
Random sampling and reconstruction of signals with finite rate of innovation
Yingchun Jiang, Junjian ZhaoAbstract : In this paper, we mainly study the random sampling and reconstruction of signals living in the subspace $V^p(\Phi,\Lambda)$ of $L^p(\mathbb{R}^d)$, which is generated by a family of molecules $\Phi$ located on a relatively separated subset $\Lambda\subset \mathbb{R}^d$. The space $V^p(\Phi,\Lambda)$ is used to model signals with finite rate of innovation, such as stream of pulses in GPS applications, cellular radio and ultra wide-band communication. The sampling set is independently and randomly drawn from a general probability distribution over $\mathbb{R}^d$. Under some proper conditions for the generators $\Phi=\{\phi_\lambda:\lambda\in \Lambda\}$ and the probability density function $\rho$, we first approximate $V^{p}(\Phi,\Lambda)$ by a finite dimensional subspace $V^{p}_N(\Phi,\Lambda)$ on any bounded domains. Then, we prove that the random sampling stability holds with high probability for all signals in $V^{p}(\Phi,\Lambda)$ whose energy concentrate on a cube when the sampling size is large enough. Finally, a reconstruction algorithm based on random samples is given for signals in $V^{p}_N(\Phi,\Lambda)$.
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2022-03-31
Variations in writhes of virtual knots under a local move
Amrendra Gill, Prabhakar MadetiAbstract : $n$-writhes denoted by $J_n(K)$ are virtual knot invariants for $n\neq 0$ and are closely associated with coefficients of some polynomial invariants of virtual knots. In this work, we investigate the variations of $J_n(K)$ under arc shift move and conclude that $n$-writhes $J_n(K)$ vary randomly in the sense that it may change by any random integer value under one arc shift move. Also, for each $n\neq 0$ we provide an infinite family of virtual knots which can be distinguished by $n$-writhes $J_n(K)$, whereas odd writhe $J(K)$ fails to do so.
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2022-03-31
Positive expansivity, chain transitivity, rigidity, and specification on general topological spaces
Thiyam Thadoi Devi, Khundrakpam Binod MangangAbstract : We discuss the notions of positive expansivity, chain transitivity, uniform rigidity, chain mixing, weak specification, and pseudo orbital specification in terms of finite open covers for Hausdorff topological spaces and entourages for uniform spaces. We show that the two definitions for each notion are equivalent in compact Hausdorff spaces and further they are equivalent to their standard definitions in compact metric spaces. We show that a homeomorphism on a Hausdorff uniform space has uniform $h$-shadowing if and only if it has uniform shadowing and its inverse is uniformly equicontinuous. We also show that a Hausdorff positively expansive system with a Hausdorff shadowing property has Hausdorff $h$-shadowing.
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2022-03-31
Packing trees into complete k-partite graph
Yanling Peng, Hong WangAbstract : In this work, we confirm a weak version of a conjecture proposed by Hong Wang. The ideal of the work comes from the tree packing conjecture made by Gy\'arf\'as and Lehel. Bollob\'as confirms the tree packing conjecture for many small tree, who showed that one can pack $T_1,T_2,\ldots,T_{n/\sqrt{2}}$ into $K_n$ and that a better bound would follow from a famous conjecture of Erd\H{o}s. In a similar direction, Hobbs, Bourgeois and Kasiraj made the following conjecture: Any sequence of trees $T_1,T_2,\ldots,T_n$, with $T_i$ having order $i$, can be packed into $K_{n-1,\lceil n/2\rceil}$. Further Hobbs, Bourgeois and Kasiraj \cite{3} proved that any two trees can be packed into a complete bipartite graph $K_{n-1,\lceil n/2\rceil}$. Motivated by the result, Hong Wang propose the conjecture: For each $k$-partite tree $T(\mathbb{X})$ of order $n$, there is a restrained packing of two copies of $T(\mathbb{X})$ into a complete $k$-partite graph $B_{n+m}(\mathbb{Y})$, where $m=\lfloor\frac{k}{2}\rfloor$. Hong Wong \cite{4} confirmed this conjecture for $k=2$. In this paper, we prove a weak version of this conjecture.
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2022-03-31
Rigidity of a rank $1$ cusp of punctured-surface groups in hyperbolic $4$-space
Youngju KimAbstract : We prove that a punctured-torus group of hyperbolic $4$-space which keeps an embedded hyperbolic $2$-plane invariant has a strictly parabolic commutator. More generally, this rigidity persists for a punctured-surface group.
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2022-03-31
Some irrational quartic threefolds
Kyusik Hong, Joonyeong WonAbstract : We study the factoriality of a nodal quartic hypersurface $V_4$ in $\mathbb{P}^4$ when there is a hyperplane in $\mathbb{P}^4$ containing all the nodes of $V_4$. As an application, we obtain new examples of irrational quartic $3$-folds.
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2022-03-31
Harmonicity of almost Norden submersions between almost Norden manifolds
Garima Gupta, Rakesh Kumar, Rachna Rani, Rashmi SachdevaAbstract : We define an almost Norden submersion (holomorphic and semi-Riemannian submersion) between almost Norden manifolds and \linebreak show that, in most of the cases, the base manifold has the similar kind of structure as that of total manifold. We obtain necessary and sufficient conditions for almost Norden submersion to be a totally geodesic map. We also derive decomposition theorems for the total manifold of such submersions. Moreover, we study the harmonicity of almost Norden submersions between almost Norden manifolds and between Kaehler-Norden manifolds. Finally, we derive conditions for an almost Norden submersion to be a harmonic morphism.
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2022-03-31
Some commutative rings defined by multiplication like-conditions
Mohamed Chhiti, Soibri MoindzeAbstract : In this article we investigate the transfer of multiplication-like properties to homomorphic images, direct products and amalgamated duplication of a ring along an ideal. Our aim is to provide examples of new classes of commutative rings satisfying the above-mentioned properties.
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2022-03-31
Area properties associated with strictly convex curves
Shin-Ok Bang, Dong-Soo Kim, Incheon KimAbstract : Archimedes proved that for a point $P$ on a parabola $X$ and a chord $AB$ of $X$ parallel to the tangent of $X$ at $P$, the area of the region bounded by the parabola $X$ and the chord $AB$ is four thirds of the area of the triangle $\bigtriangleup ABP$. This property was proved to be a characteristic of parabolas, so called the Archimedean characterization of parabolas. In this article, we study strictly convex curves in the plane ${\mathbb R}^{2}$. As a result, first using a functional equation we establish a characterization theorem for quadrics. With the help of this characterization we give another proof of the Archimedean characterization of parabolas. Finally, we present two related conditions which are necessary and sufficient for a strictly convex curve in the plane to be an open arc of a parabola.
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2022-03-31
Trace Properties and Integral Domains, III
Thomas G. Lucas, Abdeslam MimouniAbstract : An integral domain $R$ is an RTP domain (or has the radical trace property) (resp.~an $LTP$ domain) if $I(R:I)$ is a radical ideal for each nonzero noninvertible ideal $I$ (resp.~$I(R:I)R_P=PR_P$ for each minimal prime $P$ of $I(R:I)$). Clearly each RTP domain is an LTP domain, but whether the two are equivalent is open except in certain special cases. In this paper, we study the descent of these notions from particular overrings of $R$ to $R$ itself.
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2022-03-31
Mean values of derivatives of $L$-functions in even characteristic
Sunghan Bae, Hwanyup JungAbstract : For any positive integer $\mu$, we compute the mean value of the $\mu$-th derivative of quadratic Dirichlet $L$-functions over the rational function field $\mathbb{F}_{q}(t)$, where $q$ is a power of $2$.
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2022-03-31
Goldie extending property on the class of $z$-closed submodules
Adnan Tercan, Ramazan Ya\c{s}ar, Canan Celep Y\"ucelAbstract : In this article, we define a module $M$ to be $G^{\, z}$-extending if and only if for each $z$-closed submodule $X$ of $M$ there exists a direct summand $D$ of $M$ such that $X\cap D$ is essential in both $X$ and $D$. We investigate structural properties of $G^{\, z}$-extending modules and locate the implications between the other extending properties. We deal with decomposition theory as well as ring and module extensions for $G^{\, z}$-extending modules. We obtain that if a ring is right $G^{\, z}$-extending, then so is its essential overring. Also it is shown that the $G^{\, z}$-extending property is inherited by its rational hull. Furthermore it is provided some applications including matrix rings over a right $G^{\, z}$-extending ring.
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2022-03-31
On vanishing theorems for locally conformally flat Riemannian manifolds
Dang Tuyen Nguyen, Duc Thoan PhamAbstract : In this paper, we obtain some vanishing theorems for $p$-harmonic 1-forms on locally conformally flat Riemannian manifolds which admit an integral pinching condition on the curvature operators.
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2022-03-31
Various shadowing properties for time varying maps
Javad Nazarian SarkoohAbstract : This paper is concerned with the study of various notions of shadowing of dynamical systems induced by a sequence of maps, so-called time varying maps, on a metric space. We define and study the shadowing, h-shadowing, limit shadowing, s-limit shadowing and exponential limit shadowing properties of these dynamical systems. We show that h-shadowing, limit shadowing and s-limit shadowing properties are conjugacy invariant. Also, we investigate the relationships between these notions of shadowing for time varying maps and examine the role that expansivity plays in shadowing properties of such dynamical systems. Specially, we prove some results linking s-limit shadowing property to limit shadowing property, and h-shadowing property to s-limit shadowing and limit shadowing properties. Moreover, under the assumption of expansivity, we show that the shadowing property implies the h-shadowing, s-limit shadowing and limit shadowing properties. Finally, it is proved that the uniformly contracting and uniformly expanding time varying maps exhibit the shadowing, limit shadowing, s-limit shadowing and exponential limit shadowing properties.
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2022-03-31
Time stepwise local volatility
Hyeong-Ohk Bae, Hyuncheul LimAbstract : We propose a path integral method to construct a time stepwise local volatility for the stock index market under Dupire's model. Our method is focused on the pricing with the Monte Carlo Method (MCM). We solve the problem of randomness of MCM by applying numerical integration. We reconstruct this task as a matrix equation. Our method provides the analytic Jacobian and Hessian required by the nonlinear optimization solver, resulting in stable and fast calculations.
March, 2022 | Volume 59, No. 2
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On the existence of Graham partitions with congruence conditions
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On weighted Browder spectrum
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Admissible balanced pairs over formal triangular matrix rings
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One-sided fattening of the graph in the real projective plane
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On weighted Browder spectrum
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