Sahand Communications in Mathematical Analysis
Volume:20 Issue: 3, Summer 2023

In the 1920s, D. Hilbert has showed that the tensor of stress-energy, related to a given functional $\Lambda$, is a conservative symmetric bicovariant tensor $\Theta$ at the critical points of $\Lambda$, which means that div$\Theta =0$. As a routine extension, the bi-conservative condition (i.e. div$\Theta_2=0$) on  the tensor of stress-bienergy  $\Theta_2$ is introduced by G. Y. Jiang (in 1987). This subject has been followed by many mathematicians. In this paper, we study an extended version of bi-conservativity condition on the Lorentz hypersurfaces of the Einstein space. A Lorentz hypersurface $M_1^3$ isometrically immersed into the Einstein space is called $\mathcal{C}$-bi-conservative if it satisfies the condition $n_2(\nabla H_2)=\frac{9}{2} H_2\nabla H_2$, where $n_2$ is the second Newton transformation, $H_2$ is the 2nd mean curvature function on $M_1^3$ and $\nabla$ is the gradient tensor. We show that the $C$-bi-conservative Lorentz hypersurfaces of Einstein space have constant second mean curvature.

In this paper, we introduce a convolution-type product for  strongly integrable Hilbert $C^*$-module valued maps on locally compact groups. We investigate various properties of this product related to uniform continuity, boundless, etc. For instance, we prove a convolution theorem. Also, we study the boundless of the  related convolution operator in various settings.

In this paper, by employing  sine hyperbolic inverse functions,  we  introduced the generalized  subfamily $\mathcal{RK}_{\sinh}(\beta)$ of analytic functions defined on the open unit disk $\Delta:=\{\xi: \xi \in \mathbb{C} \text{ and } |\xi|<1 \}$ associated with the petal-shaped domain. The bounds of the first three Taylor-Maclaurin's coefficients, Fekete-Szeg\"{o} functional and the second Hankel determinants are investigated for $f\in\mathcal{RK}_{\sinh}(\beta)$. We considered Borel distribution as an application to our main results. Consequently, a number of corollaries have been made based on our results, generalizing previous studies in this direction.

Let $\varphi:A\to B$ be an isomorphism of $C^*$-algebras and $I$ be an ideal of $A.$  Introducing the concepts of unitary equivalent and the implemented Finsler modules, we show that the $\frac{A}{I}$-module $\frac{E}{E_{I}}$ and the implemented  $\frac{B}{\varphi(I)}$-module  $\frac{F}{F_{\varphi(I)}}$  are unitary equivalent. We also,  establish a one to one correspondence between  the groups $U(E)$ and $U(F)$ of  unitaries on full Finsler modules $E$ and $F,$ respectively.   Finally, we explain regularized  dynamical systems and   apply the aforementioned one to one correspondence to prove that  each regularized  dynamical system in $U(E)$ implements a   regularized  dynamical system  in $U(F).$

In this work,  we consider product-type  operators $T^m_{u,v,\varphi}$ from minimal M\"{o}bius invariant spaces into Zygmund-type spaces.  Firstly, some characterizations for   the boundedness of these operators are given. Then some estimates of the essential norms of these operators are obtained. Therefore, some compactness conditions will be given.

In this paper, we introduce the class of strongly $m$--$MT$-convex functions  based on the identity given in [P. Cerone et al., 1999]. We establish new inequalities of the Ostrowski-type for functions whose $n^{th}$ derivatives are strongly $m$--$MT$-convex functions.

In the literature, several papers are devoted to inequalities of Simpson-type in the case of differentiable convex functions and fractional versions. Moreover, some papers are focused on inequalities of Simpson-type for twice differentiable convex functions. In this research article, we obtain an identity for twice differentiable convex functions. Then, we prove several fractional inequalities of Simpson-type for convex functions.

This article deals with the existence, uniqueness and Ulam type stability results for a class of boundary value problems for fractional differential equations with Riesz-Caputo fractional derivative. The results are based on Banach contraction principle and Krasnoselskii's fixed point theorem. An illustrative example is given to validate our main results.

A system of generalized mixed variational inclusion problem (SGMVIP) is considered involving $H(.,.)$-mixed mappings in $q$-uniformly smooth Banach spaces. By means of proximal-point mapping method, the existence of solution of this system of variational inclusions is given. A new two-step iterative algorithm is proposed for solving SGMVIP. Strong convergence of the proposed algorithm is given.

In this paper, we define and consider, the category {\bf FPos}-$S$ of all $S$-fuzzy posets and action-preserving monotone maps between them. $S$-fuzzy poset congruences which play an important role in studying thecategorical properties of $S$-fuzzy posets are introduced. More precisely, the correspondence between the $S$-fuzzy poset congruences and the fuzzy action and order preserving maps is discussed. We characterize $S$-fuzzy poset congruences on the $S$-fuzzy posets in terms of the fuzzy pseudo orders. Some categorical properties of the category {\bf FPos}-$S$ of all $S$-fuzzy posets is considered. In particular, we characterize products, coproducts, equalizers, coequalizers, pullbacks and pushouts in this category. Also, we consider all forgetful functors between the category {\bf FPos}-$S$ and the categories {\bf FPos} of fuzzy posets, {\bf Pos}-$S$ of $S$-posets, {\bf Pos} of posets, {\bf Act}-$S$ of $S$-acts  and {\bf Set} of sets and study the existence of their left and right adjoints. Finally, epimorphisms, monomorphisms and order embeddings in {\bf FPos} and {\bf FPos}-$S$ are studied.