Afrika Matematika最新文献

We compute certain inequalities for B-Berezin radius of (2times 2) operator matrices in the study that generalize and refine earlier inequalities. Furthermore, we construct A-Berezin radius inequalities of operators in (mathbb {B}_{A,Upsilon }(mathcal {H})) that improve on the current inequalities in Huban (Turk J Math 46(1):189–206, 2022). In addition, we establish A-Berezin radius bounds for sum of product of operators in (mathbb {B}_{A,Upsilon } (mathcal {H}),) which improve on the previous bounds.

In this paper, we investigate the existence and specific form of finite order transcendental entire solutions of certain equations including a Fermat-type functional first-order linear difference equation in (mathbb {C}^n), (ngeqslant 2) and a kth order partial differential difference equation in (mathbb {C}^2). The paper builds upon the previous works of Xu and Cao (Mediterr J Math 15:1–14, 2018; Mediterr J Math 17:1–4, 2020) and Haldar (Mediterr J Math 20: 50, 2023) whose results are extended and further developed in this study. We exhibit several examples to demonstrate the precision and applicability of our results to illustrate how our findings can be utilized in different scenarios or problem contexts. Towards the end of the paper, in the last section, we discuss some relevant questions that have emerged from one of the examples in the paper which also suggest potential directions for further research.

In this paper we establish some fixed point results for continuous countably condensing maps. We derive results of Altman’s type, Leray-Schauder’s type, Krasnosel’skii’s type and Krasnoselskii-Schafer’s type. One of the main tools in our analysis is a result due to S. J. Daher (Theorem 2.1). We conclude the paper by discussing existence results for a nonlinear Volterra integral equation.

Fuzzy rough set theory gives a mathematical tool for studying unsettled knowledge that is beclouded, inexact, and mutually exclusive. The perception and conclusions of fuzzy rough sets theory are inextricably linked to topological perception. The topological appearance and its applications in fuzzy rough sets theory have been extensively discussed by researchers. The underlying subordinate of topology and classic fuzzy rough sets theory, as well as the expressive work done in this area over the previous years, are highlighted in this research.

The generator of the semigroup associated with linear age-structured population models including spatial diffusion is shown to have compact resolvent.

This paper investigates the performance of combined and separate log type class of estimators of population mean under stratified ranked set sampling. The expressions of bias and mean square error of the proposed estimators are deduced. The theoretical comparison of the proposed estimators with the existing estimators is carried out and the efficiency conditions are reported. The credibility of theoretical results is extended by a simulation study conducted over various artificially generated symmetric and asymmetric populations. The results of the simulation study show that the proposed class of estimators dominate the well-known existing estimators.

Let (g_1) and (g_2 ) be any two analytic functions defined in the unit disc which are normalized by the condition (g_1(0)=1=g_2(0)) and (sigma _n^{b-1,c}(z)) be the n th Cesàro mean of type ((b-1,c)) for (1+b>c>0). Then (g_1) is generalized Cesàro stable with respect to (g_2), whenever

where (sigma _n^{b-1,c}(g,z) = dfrac{1}{B_n} sum _{j=0}^{n} B_{n-j} b_j z^j = sigma _n^{b-1,c}(z) * g(z)). The main aim of this article is to prove that (left( {(Az+1)}/{(Bz+1)}right) ^eta ) is generalized Cesàro stable with respect to ((1/(Bz+1)^{eta })) but not with respect to itself for (-1 le B < A le 0) and (0<eta le 1). As an application, we obtain new and existing results on Cesàro stability and stability.

In this paper, we give some new sharp bounds for sinc and hyperbolic sinc functions via cosine and hyperbolic cosine functions, which these bounds refine or improve most of recent published results.

We derive general formula for the fourth coefficient of the functions belonging to the Carathéodory class involving the parameters lying in the open unit disk. Further, we obtain sharp upper bounds of initial inverse coefficients for certain close-to-convex functions satisfying any one of the inequalities: (text {Re}((1-z)f^{'}(z))>0,text {Re}((1-z^2)f^{'}(z))>0,text {Re}((1-z+z^2)f^{'}(z))>0) and (text {Re}((1-z)^2f^{'}(z))>0).

In this paper, we focus on affine generalized Ricci solitons with respect to the perturbed canonical connection and the perturbed Kobayashi–Nomizu connection on three-dimensional Lorentzian Lie groups and we find the detailed classification of these affine generalized Ricci solitons with product structure on three-dimensional Lorentzian Lie groups.