Abstract : Given a sequence of point blow-ups of smooth $n-$dimensional projective varieties $Z_{i}$ defined over an algebraically closed field $\mathit{k}$, $Z_{s}\xrightarrow{\pi_{s}} Z_{s-1}\xrightarrow{\pi_{s-1}}\cdot\cdot\cdot\xrightarrow{\pi_{2}} Z_{1}\xrightarrow{\pi_{1}} Z_{0}$, with $Z_{0}\cong\mathbb{P}^{n}$, we give two presentations of the Chow ring $A^{\bullet}(Z_{s})$ of its sky. The first one uses the classes of the total transforms of the exceptional components as generators and the second one uses the classes of the strict transforms ones. We prove that the skies of two sequences of point blow-ups of the same length have isomorphic Chow rings. Finally we give a characterization of the final divisors of a sequence of point blow-ups in terms of some relations defined over the Chow group of zero-cycles $A_{0}(Z_{s})$ of its sky.
Abstract : Let $R$ be a commutative ring with $1\neq 0.$ Let $Id(R)$ be the set of all ideals of $R$ and let $\delta: Id(R)\longrightarrow Id(R)$ be a function. Then $\delta$ is called an expansion function of the ideals of $R$ if whenever $L, I, J$ are ideals of $R$ with $J\subseteq I,$ then $L\subseteq \delta(L)$ and $\delta(J)\subseteq \delta(I).$ Let $\delta$ be an expansion function of the ideals of $R$ and $m\geq n>0$ be positive integers. Then a proper ideal $I$ of $R$ is called an \textit{$(m,n)$-closed $\delta$-primary ideal} (resp., \textit{weakly $(m,n)$-closed $\delta$-primary ideal}) if $a^{m}\in I$ for some $a\in R$ implies $a^{n}\in\delta(I)$ (resp., if $0\neq a^{m}\in I$ for some $a\in R$ implies $a^{n}\in\delta(I)).$ Let $f:A\longrightarrow B$ be a ring homomorphism and let $J$ be an ideal of $B.$ This paper investigates the concept of $(m,n)$-closed $\delta$-primary ideals in the amalgamation of $A$ with $B$ along $J$ with respect to $f$ denoted by $A\bowtie^{f}J.$
Abstract : Let $\mathscr{K}$ be a ring. An additive map $\mathfrak{u}^\diamond\rightarrow \mathfrak{u}$ is called Jordan involution on $\mathscr{K}$ if $(\mathfrak{u}^\diamond)^\diamond=\mathfrak{u}$ and $(\mathfrak{u}\mathfrak{v}+\mathfrak{v}\mathfrak{u})^\diamond=\mathfrak{u}^{\diamond}\mathfrak{v}^{\diamond}+\mathfrak{v}^{\diamond}\mathfrak{u}^{\diamond}$ for all $\mathfrak{u},\mathfrak{v}\in \mathscr{K}$. If $\Theta$ is a (non-zero) $\eta-$generalized derivation on $\mathscr{K}$ associated with a derivation $\Omega$ on $\mathscr{K}$, then it is shown that $\Theta(\mathfrak{u})=\gamma \mathfrak{u}$ for all $\mathfrak{u}\in \mathscr{K}$ such that $\gamma\in \Xi$ and $\gamma^2=1$, whenever $\Theta$ possesses $[\Theta(\mathfrak{u}), \Theta(\mathfrak{u}^\diamond)]=[\mathfrak{u},\mathfrak{u}^\diamond]$ for all $\mathfrak{u}\in \mathscr{K}$.
Abstract : In this article, we study a certain class of partitioning ideals known as $Q$-ideals, in semirings. Main objective is to investigate differential identities linking a semiring $S$ to its prime $Q$-ideal $I_Q$, which ensure the commutativity and other features of $S/I_Q$.
Abstract : The purpose of this paper is to introduce a new class of rings containing the class of $m$-formally Noetherian rings and contained in the class of nonnil-SFT rings introduced and investigated by Benhissi and Dabbabi in 2023 \cite{Amir}. Let $A$ be a commutative ring with a unit. The ring $A$ is said to be nonnil-$m$-formally Noetherian, where $m\geq 1$ is an integer, if for each increasing sequence of nonnil ideals $(I_n)_{n\geq 0}$ of $A$ the (increasing) sequence $(\sum_{i_1+\cdots+i_m=n}I_{i_1}I_{i_2}\cdots I_{i_m})_{n\geq 0}$ is stationnary. We investigate the nonnil-$m$-formally Noetherian variant of some well known theorems on Noetherian and $m$-formally Noetherian rings. Also we study the transfer of this property to the trivial extension and the amalgamation algebra along an ideal. Among other results, it is shown that $A$ is a nonnil-$m$-formally Noetherian ring if and only if the $m$-power of each nonnil radical ideal is finitely generated. Also, we prove that a flat overring of a nonnil-$m$-formally Noetherian ring is a nonnil-$m$-formally Noetherian. In addition, several characterizations are given. We establish some other results concerning $m$-formally Noetherian rings.
Abstract : This paper introduces and studies a generalization of $(n,d)$-rings introduced and studied by Costa in 1994 to rings with prime nilradical. Among other things, we establish that the $\phi$-von Neumann regular rings are exactly either $\phi$-$(0,0)$ or $\phi$-$(1,0)$ rings and that the $\phi$-Pr\"ufer rings which are strongly $\phi$-rings are the $\phi$-$(1,1)$ rings. We then introduce a new class of rings generalizing the class of $n$-coherent rings to characterize the nonnil-coherent rings introduced and studied by Bacem and Benhissi.
Abstract : In this note, we aim to correct some of the results presented in \cite{Fernandes:2023}. Namely, the statements of Proposition 2.1, Corollary 2.2, Corollary 2.3, Theorem 2.4 and Theorem 2.6, concerning only the monoids $\mathcal{O}\mathcal{P}_n$ and $\mathcal{P}\mathcal{O}\mathcal{P}_n$, have to exclude transformations of rank two. All other results of \cite{Fernandes:2023}, as well as those mentioned above but for the monoids $\mathcal{O}\mathcal{R}_n$ and $\mathcal{P}\mathcal{O}\mathcal{R}_n$, do not require correction.
Abstract : In this article, by making use of the $\lambda$-pseudo-starlike functions, we introduce a certain family of normalized analytic functions in the open unit disk $U$ and we establish coefficient estimates for the first four determinants of the Toeplitz matrices $T_{2}(2)$, $T_{2}(3)$, $T_{3}(2)$ and $T_{3}(1)$ for the functions belonging to this family. Further, some known and new results which follow as special cases of our results are also mentioned.
Abstract : In this paper, we use higher order derivatives with regard to symmetric points to introduce a class of multivalent starlike functions. The major deviation is that we define some differential characterizations that are subordinate to a function whose real part is not greater than zero. The primary outcomes of this study are initial coefficients and the Fekete-Szeg\H{o} inequality for functions falling under the given class. Also, we have obtained an interesting subordination results involving symmetric functions. The results obtained here extend or unify the various other well-known and new results.
Abstract : In this work, an alternative fashion of the multi-Jensen is introduced. The structures of the multi-Jensen and the multi-Euler-Lagrange-Jensen mappings are described. In other words, the system of $n$ equations defining each of the mentioned mappings is unified as a single equation. Furthermore, by applying a fixed point theorem, the Hyers-Ulam stability for the multi-Euler-Lagrange-Jensen mappings in the setting of Banach spaces is established. An appropriate counterexample is supplied to invalidate the results in the case of singularity for multiadditive mappings.
Abstract : Let $n\in \mathbb{N}, n\geq 2$. An element $(x_1, \ldots, x_n)\in E^n$ is called a {\em norming point} of $T\in {\mathcal L}(^n E)$ if $\|x_1\|=\cdots=\|x_n\|=1$ and$|T(x_1, \ldots, x_n)|$ $=\|T\|$, where ${\mathcal L}(^n E)$ denotes the space of all continuous $n$-linear forms on $E$.For $T\in {\mathcal L}(^n E)$, we define $${Norm}(T)=\Big\{(x_1, \ldots, x_n)\in E^n: (x_1, \ldots, x_n)~\mbox{is a norming point of}~T\Big\}.$$${Norm}(T)$ is called the {\em norming set} of $T$.Let $0\leq \theta\leq \frac{\pi}{4}$ and $\ell^2_{{\infty}, \theta}=\mathbb{R}^2$ with the rotated supremum norm $$\|(x, y)\|_{({\infty}, \theta)}=\max\Big\{|x \cos \theta+y \sin \theta|,~ |x \sin \theta-y \cos \theta|\Big\}.$$In this paper, we characterize the norming set of $T\in {\mathcal L}(^n \ell_{(\infty, \theta)}^2)$. Using this result, we completely describe the norming set of $T\in {\mathcal L}_s(^n \ell_{(\infty, \theta)}^2)$ for $n=3, 4, 5$, where ${\mathcal L}_s(^n \ell_{(\infty, \theta)}^2)$ denotes the space of all continuous symmetric $n$-linear forms on $\ell_{(\infty, \theta)}^2$. We generalizes the results from \cite{9} for $n=3$ and $\theta=\frac{\pi}{4}$.
Abstract : Let ${\mathcal B}(H)$ be the algebra of all bounded linear operators on a Hilbert space $H$ with $\operatorname{dim} (H)>2$. Let ${\mathcal{G} \mathcal{P}}$ be the subset of ${\mathcal B}(H)$ of all generalized projection operators. In this paper, we give a complete characterization of surjective maps $\Phi: {\mathcal B}(H) \rightarrow {\mathcal B}(H)$ satisfying $A-\lambda B \in {\mathcal{G} \mathcal{P}} \Leftrightarrow \Phi(A)-\lambda \Phi(B) \in {\mathcal{G} \mathcal{P}}$ for any $A, B \in {\mathcal B}(H)$ and $\lambda \in \mathbb{C}$.
Abstract : In this paper, we study the Hyers-Ulam stability of the classical iterative functional equation $f^n(x)=x$, the Babbage equation, using strictly monotonic approximate solutions on a real interval.
Abstract : The ordinary mean curvature vector field $\textbf H$ on a submanifold $M$ of a space form is said to be {\it proper} if it satisfies equality $\Delta\textbf H=a\textbf H$ for a constant real number $a$. It is proven that every hypersurface of an Riemannian space form with proper mean curvature vector field has constant mean curvature. In this manuscript, we study the Lorentzian hypersurfaces with proper second mean curvature vector field of four dimensional Lorentzian space forms. We show that the scalar curvature of such a hypersurface has to be constant. In addition, as a classification result, we show that each Lorentzian hypersurface of a Lorentzian 4-space form with proper second mean curvature vector field is $\textrm C$-biharmonic, $\textrm C$-1-type or $\textrm C$-null-2-type. Also, we prove that every $\textbf H_2$-proper Lorentzian hypersurface with constant ordinary mean curvature in a Lorentz 4-space form is 1-minimal.
Abstract : In three dimensional Euclidean space we consider kinematical invariants of the surface which is generated by the motion of a planar curve, especially, the surface which is foliated by circles. At first we characterize the properties of single parameter plane with the theories of unit spherical curve in three dimensional Euclidean space. Then using these results we give the invariants and differential invariants, kinematical properties and some special examples of the surface foliated by circles. The methods established here can be used to the other kinds of the surface in three dimensional Euclidean space.
Abstract : Let $(X, m$, $\mathcal{H})$ be a hereditary $m$-space and $\gamma : m \rightarrow P(X)$ be an operation on $m$. A subset $A$ of $X$ is said to be $\gamma\mathcal{H}$-compact relative to $X$ \cite{Al-No} if for every cover $\{ U_\alpha : \alpha \in \Delta \}$ of $A$ by $m$-open sets of $X$, there exists a finite subset $\Delta_0$ of $\Delta$ such that $A \setminus \cup\{ \gamma(U_\alpha) : \alpha \in \Delta_0 \} \in \mathcal{H}$. In this paper, we define and investigate two kinds of strong forms of $\gamma\mathcal{H}$-compact relative to $X$.
Abstract : Given $M$ a monoid with a neutral element $e$. We show that the solutions of d'Alembert's functional equation for $n\times n$ matrices \begin{equation*} \Phi(pr,qs)+\Phi(sp,rq)=2\Phi(r,s)\Phi(p,q),\quad p,q,r,s\in M \end{equation*} are abelian. Furthermore, we prove under additional assumption that the solutions of the n-dimensional mixed vector-matrix Wilson's functional equation \begin{equation*} \left\lbrace\begin{array}{ll} f(pr,qs)+f(sp,rq)=2\Phi(r,s)f(p,q),\\ \Phi(p,q)=\Phi(q,p),\quad p,q,r,s\in M \end{array}\right. \end{equation*} are abelian. As an application we solve the first functional equation on groups for the particular case of $n=3$.
Abstract : In our study, the integration of fuzzy graphs into classical graph theory gives rise to a novel concept known as ``Fuzzy Super Subdivision." Let $SS_{f}(G)$ be the fuzzy super subdivision graphs, by substituting a complete bipartite graph $k_{(2,m)}$ $(m=1,2,\ldots)$ for each edge of a fuzzy graph. The attributes and properties of this newly proposed concept are briefly outlined, in addition to illustrative examples. Furthermore, significant findings are discussed on connectivity, size, degree and order of fuzzy super subdivision structures. To illustrate the practical implications of our approach, we present an application focused on analyzing the growth of infections in blood or urine samples using the Fuzzy Super Subdivision model.
Ismael Akray, Amin Mahamad Zebari
Commun. Korean Math. Soc. 2023; 38(1): 21-38
https://doi.org/10.4134/CKMS.c210349
Vinay Kumar, Rajendra Prasad, Sandeep Kumar Verma
Commun. Korean Math. Soc. 2023; 38(1): 205-221
https://doi.org/10.4134/CKMS.c210433
Ioannis Diamantis
Commun. Korean Math. Soc. 2022; 37(4): 1221-1248
https://doi.org/10.4134/CKMS.c210169
Harish Chandra, Anurag Kumar Patel
Commun. Korean Math. Soc. 2023; 38(2): 451-459
https://doi.org/10.4134/CKMS.c220108
Vinay Kumar, Rajendra Prasad, Sandeep Kumar Verma
Commun. Korean Math. Soc. 2023; 38(1): 205-221
https://doi.org/10.4134/CKMS.c210433
Ismael Akray, Amin Mahamad Zebari
Commun. Korean Math. Soc. 2023; 38(1): 21-38
https://doi.org/10.4134/CKMS.c210349
Anjan Kumar Bhuniya, Manas Kumbhakar
Commun. Korean Math. Soc. 2023; 38(1): 1-9
https://doi.org/10.4134/CKMS.c210057
Traiwat Intarawong, Boonrod Yuttanan
Commun. Korean Math. Soc. 2023; 38(2): 355-364
https://doi.org/10.4134/CKMS.c220139
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