Abstract : In this paper, we study some properties of B\'ezout and weakly B\'ezout rings. Then, we investigate the transfer of these notions to trivial ring extensions and amalgamated algebras along an ideal. Also, in the context of domains we show that the amalgamated is a B{\'e}zout ring if and only if it is a weakly B\'ezout ring. All along the paper, we put the new results to enrich the current literature with new families of examples of non-B\'ezout weakly B\'ezout rings.
Abstract : In this paper, the concepts of $w$-linked homomorphisms, the $w_{\phi}$-operation, and DW${}_{\phi}$ rings are introduced. Also the relationships between $w_{\phi}$-ideals and $w$-ideals over a $w$-linked homomorphism $\phi: R\ra T$ are discussed. More precisely, it is shown that every $w_{\phi}$-ideal of $T$ is a $w$-ideal of $T$. Besides, it is shown that if $T$ is not a DW${}_{\phi}$ ring, then $T$ must have an infinite number of maximal $w_{\phi}$-ideals. Finally we give an application of Cohen's Theorem over $w$-factor rings, namely it is shown that an integral domain $R$ is an SM-domain with $w$-$\dim(R)\leq 1$, if and only if for any nonzero $w$-ideal $I$ of $R$, $(R/I)_w$ is an Artinian ring, if and only if for any nonzero element $a\in R$, $(R/(a))_w$ is an Artinian ring, if and only if for any nonzero element $a\in R$, $R$ satisfies the descending chain condition on $w$-ideals of $R$ containing $a$.
Abstract : It is shown that every nilpotent-invariant module can be decomposed into a direct sum of a quasi-injective module and a square-free module that are relatively injective and orthogonal. This paper is also concerned with rings satisfying every cyclic right $R$-module is nilpotent-invariant. We prove that $R\cong R_1\times R_2$, where $R_1, R_2$ are rings which satisfy $R_1$ is a semi-simple Artinian ring and $R_2$ is square-free as a right $R_2$-module and all idempotents of $R_2$ is central. The paper concludes with a structure theorem for cyclic nilpotent-invariant right $R$-modules. Such a module is shown to have isomorphic simple modules $eR$ and $fR$, where $e,f$ are orthogonal primitive idempotents such that $eRf\ne 0$.
Abstract : Zero-difference balanced (ZDB) functions can be applied to many areas like optimal constant composition codes, optimal frequency hopping sequences etc. Moreover, it has been shown that the image set of some ZDB functions is a regular partial difference set, and hence provides strongly regular graphs. Besides, perfect nonlinear functions are zero-difference balanced functions. However, the converse is not true in general. In this paper, we use the decomposition of cyclotomic polynomials into irreducible factors over $\mathbb F_p$, where $p$ is an odd prime to generalize some recent results on ZDB functions. Also we extend a result introduced by Claude et al. [3] regarding zero-difference-$p$-balanced functions over $\mathbb F_{p^n}$. Eventually, we use these results to construct some optimal constant composition codes.
Abstract : In this paper, for a transcendental meromorphic function $f$ and $a\in \mathbb{C}$, we have exhaustively studied the nature and form of solutions of a new type of non-linear differential equation of the following form which has never been investigated earlier: \[f^n+af^{n-2}f'+ P_d(z,f) = \sum_{i=1}^{k}p_i(z)e^{\alpha_i(z)}, \] where $P_d(z,f)$ is a differential polynomial of $f$, $p_i$'s and $\alpha_{i}$'s are non-vanishing rational functions and non-constant polynomials, respectively. When $a=0$, we have pointed out a major lacuna in a recent result of Xue [17] and rectifying the result, presented the corrected form of the same equation at a large extent. In addition, our main result is also an improvement of a recent result of Chen-Lian [2] by rectifying a gap in the proof of the theorem of the same paper. The case $a\neq 0$ has also been manipulated to determine the form of the solutions. We also illustrate a handful number of examples for showing the accuracy of our results.
Abstract : In this paper, we show that under certain conditions the Wedderburn decomposition of a finite semisimple group algebra $\mathbb{F}_qG$ can be deduced from a subalgebra $\mathbb{F}_q(G/H)$ of factor group $G/H$ of $G$, where $H$ is a normal subgroup of $G$ of prime order $P$. Here, we assume that $q=p^r$ for some prime $p$ and the center of each Wedderburn component of $\mathbb{F}_qG$ is the coefficient field $\mathbb{F}_q$.
Abstract : We formulate the matrix representation of a composition operator on the Hardy space of the unit disc with the symbol which is a Riemann map of the unit disc, with respect to a special orthonormal basis.
Abstract : Given an ACM set $\mathbb{X}$ of points in a multiprojective space $\mathbb{P}^{m}\!\times\mathbb{P}^{n}$ over a field of characteristic zero, we are interested in studying the K\"ahler different and the Cayley-Bacharach property for $\mathbb{X}$. In $\mathbb{P}^1\times \mathbb{P}^1$, the Cayley-Bacharach property agrees with the complete intersection property and it is characterized by using the K\"ahler different. However, this result fails to hold in $\mathbb{P}^{m}\!\times\mathbb{P}^{n}$ for $n>1$ or $m>1$. In this paper we start an investigation of the K\"ahler different and its Hilbert function and then prove that $\mathbb{X}$ is a complete intersection of type $(d_1,\ldots,d_m,d'_1,\ldots,d'_n)$ if and only if it has the Cayley-Bacharach property and the K\"ahler different is non-zero at a certain degree. We characterize the Cayley-Bacharach property of $\mathbb{X}$ under certain assumptions.
Abstract : In this paper, we announce that the strategy of comparing the complex moments of $L(1,\chi_{u})$ to that of a random Euler product $L(1, {\mb X})$ is also valid in even characteristic case. We give an asymptotic formulas for the complex moments of $L(1,\chi_{u})$ in a large uniform range. We also give $\Omega$-results for the extreme values of $L(1,\chi_{u})$.
Abstract : We prove sharp bounds for Hankel determinants for starlike functions $f$ with respect to symmetrical points, i.e., $f$ given by $f(z)=z+\sum_{n=2}^{\infty}a_nz^n$ for $z\in \mathbb{D}$ satisfying $$ Re\dfrac{zf'(z)}{f(z)-f(-z)}>0, \quad z\in \mathbb{D}. $$ We also give sharp upper and lower bounds when the coefficients of $f$ are real.
St\'ephane R. Louboutin
Bull. Korean Math. Soc. 2023; 60(1): 1-22
https://doi.org/10.4134/BKMS.b210464
Esmaiel Abedi, Najma Mosadegh
Bull. Korean Math. Soc. 2022; 59(6): 1595-1603
https://doi.org/10.4134/BKMS.b210910
Guangzhou Chen , Wen Li, Bangying Xin, Ming Zhong
Bull. Korean Math. Soc. 2022; 59(3): 617-642
https://doi.org/10.4134/BKMS.b210281
Yu Wang
Bull. Korean Math. Soc. 2023; 60(4): 1025-1034
https://doi.org/10.4134/BKMS.b220460
Donghoon Jang
Bull. Korean Math. Soc. 2023; 60(5): 1295-1298
https://doi.org/10.4134/BKMS.b220657
Mustafa Altın, Ahmet Kazan, Dae Won Yoon
Bull. Korean Math. Soc. 2023; 60(5): 1299-1320
https://doi.org/10.4134/BKMS.b220680
Xiaoli Chao, Weili Wang
Bull. Korean Math. Soc. 2023; 60(3): 623-636
https://doi.org/10.4134/BKMS.b210927
Gurpreet Kaur, Sumit Nagpal
Bull. Korean Math. Soc. 2023; 60(6): 1477-1496
https://doi.org/10.4134/BKMS.b220582
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