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Refined Kato inequality and applications to norm and numerical radius inequalities RACSAM (IF 2.9) Pub Date : 2024-04-24 Fuad Kittaneh, Hamid Reza Moradi, Mohammad Sababheh
In this paper, we present refinements of Kato’s inequality; then, we employ these refinements to obtain some norm and numerical radius inequalities. Our results improve some celebrated inequalities in the literature.
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Banach spaces with small weakly open subsets of the unit ball and massive sets of Daugavet and $$\Delta $$ -points RACSAM (IF 2.9) Pub Date : 2024-04-22 Christian Cobollo, Daniel Isert, Ginés López-Pérez, Miguel Martín, Yoël Perreau, Alicia Quero, Andrés Quilis, Daniel L. Rodríguez-Vidanes, Abraham Rueda Zoca
We prove that there exists an equivalent norm \(\left| \left| \left| \cdot \right| \right| \right| \) on \(L_\infty [0,1]\) with the following properties: (1) The unit ball of \((L_\infty [0,1],\left| \left| \left| \cdot \right| \right| \right| )\) contains non-empty relatively weakly open subsets of arbitrarily small diameter; (2) The set of Daugavet points of the unit ball of \((L_\infty [0,1],\left|
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Optimality conditions and Lipschitz stability for non-smooth semilinear elliptic optimal control problems with sparse controls RACSAM (IF 2.9) Pub Date : 2024-04-21 Vu Huu Nhu, Phan Quang Sang
This paper is concerned with first- and second-order optimality conditions as well as the stability for non-smooth semilinear optimal control problems involving the \(L^1\)-norm of the control in the cost functional. In addition to the appearance of the \(L^1\)-norm leading to the non-differentiability of the objective and promoting the sparsity of the optimal controls, the non-smoothness of the nonlinear
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Conformally flat centroaffine Tchebychev hypersurfaces RACSAM (IF 2.9) Pub Date : 2024-04-18 Cece Li, Huiyang Xu
In this paper, we study locally strongly convex, conformally flat centroaffine hypersurfaces. The key step is to obtain some relations between the Schouten operator P, the difference tensor and its traceless tensor, which is achieved by applying the Tsinghua principle for two related symmetric Codazzi tensors of (1, 2)-form on a conformally flat manifold. As the main results, (1) such hypersurfaces
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On the full range of Zippin and inclusion indices of rearrangement-invariant spaces RACSAM (IF 2.9) Pub Date : 2024-04-17 Guillermo P. Curbera, Oleksiy Karlovych, Eugene Shargorodsky
Let X be a rearrangement-invariant space on [0, 1]. It is known that its Zippin indices \(\underline{\beta }{}_X,\overline{\beta }{}_X\) and its inclusion indices \(\gamma _X,\delta _X\) are related as follows: \(0\le \underline{\beta }{}_X\le 1/\gamma _X \le 1/\delta _X\le \overline{\beta }{}_X\le 1\). We show that given \(\underline{\beta },\overline{\beta }\in [0,1]\) and \(\gamma ,\delta \in [1
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Formulas for p-adic q-integrals including falling-rising factorials, combinatorial sums and special numbers RACSAM (IF 2.9) Pub Date : 2024-04-16 Yilmaz Simsek
The main purpose of this paper is to provide a novel approach to deriving formulas for the p-adic q-Volkenborn integral including the Volkenborn integral and p-adic fermionic integral. By applying integral equations and these integral formulas to the falling factorials, the rising factorials and binomial coefficients, we derive some various identities, formulas and relations related to several combinatorial
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Generating operators between Banach spaces RACSAM (IF 2.9) Pub Date : 2024-04-13 Vladimir Kadets, Miguel Martín, Javier Merí, Alicia Quero
We introduce and study the notion of generating operators as those norm-one operators \(G:X\longrightarrow Y\) such that for every \(0<\delta <1\), the set \(\{x\in X:\Vert x\Vert \leqslant 1,\ \Vert Gx\Vert >1-\delta \}\) generates the unit ball of X by closed convex hull. This class of operators includes isometric embeddings, spear operators (actually, operators with the alternative Daugavet property)
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Group invariant variational principles RACSAM (IF 2.9) Pub Date : 2024-04-13 Javier Falcó, Daniel Isert
In this paper we introduce a group invariant version of the well-known Ekeland variational principle. To achieve this, we define the concept of convexity with respect to a group and establish a version of the theorem within this framework. Additionally, we present several consequences of the group invariant Ekeland variational principle, including Palais-Smale minimizing sequences, the Brønsted-Rockafellar
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Weak Amenability of Banach Algebra-Valued $$\ell _p$$ -Sequence Algebras RACSAM (IF 2.9) Pub Date : 2024-04-12 Krzysztof Koczorowski, Krzysztof Piszczek
We characterize weak amenability of Banach algebras of the form \(c_0(A)\) and \(\ell _p(A)\), where A is an arbitrary Banach algebra and \(1\leqslant p<\infty \). Specifically, we generalize the case of \(\ell _1(A)\) for a \(C^*\)-algebra A. We also discuss amenability and contractibility of these algebras.
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Local Korovkin-type approximation problems for bounded function spaces RACSAM (IF 2.9) Pub Date : 2024-04-11 Francesco Altomare
The paper is concerned with some local approximation problems by special classes of positive linear operators acting on spaces of Borel measurable bounded functions on a compact metric space. A Korovkin-type criterion is established with respect to a given positive linear operator, the convergence being required uniformly on arbitrary but fixed compact subsets. Several special cases are discussed where
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Embedding the free topological group $$F(X^n)$$ into F(X) RACSAM (IF 2.9) Pub Date : 2024-04-10 Arkady G. Leiderman, Mikhail G. Tkachenko
In 1976, Nickolas showed that for each natural n, the free topological group \(F(X^n)\) is topologically isomorphic to a subgroup of F(X) provided X is a compact space or, more generally, a \(k_{\omega }\)-space. We complement the Nickolas’ embedding theorem by showing that it remains true for every topological space X such that all finite powers of X are pseudocompact. For example, all pseudocompact
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The Kotake–Narasimhan theorem in general ultradifferentiable classes RACSAM (IF 2.9) Pub Date : 2024-04-09 Stefan Fürdös
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Stability properties of ultraholomorphic classes of Roumieu-type defined by weight matrices RACSAM (IF 2.9) Pub Date : 2024-04-06 Javier Jiménez-Garrido, Ignacio Miguel-Cantero, Javier Sanz, Gerhard Schindl
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A class of the Newtonian HK-Sobolev spaces on metric measure spaces RACSAM (IF 2.9) Pub Date : 2024-04-06 H. M. Srivastava, Parthapratim Saha, Bipan Hazarika
In this article, the authors present a systematic study of a class of the Newtonian HK-Sobolev spaces on metric measure spaces. Several Sobolev-type embeddings are discussed in the context of the Newtonian HK-Sobolev spaces. As an application, the boundedness of the fractional maximal operator on the Newtonian HK-Sobolev spaces is also investigated.
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On Ulam stabilities of iterative Fredholm and Volterra integral equations with multiple time-varying delays RACSAM (IF 2.9) Pub Date : 2024-04-02 Osman Tunç, Cemil Tunç
In present study, we deal with nonlinear iterative Fredholm and Volterra integral equations (Fredholm and Volterra IEs) including variable time delays. We are interested here in the investigations of the uniqueness of solutions and Ulam type stabilities of that the iterative Fredholm and the Volterra IEs. The proofs of the new outcomes of the study with regard to these concepts are done in the light
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Inheritance of quasinilpontency and Drazin invertibility between a matrix and its entry RACSAM (IF 2.9) Pub Date : 2024-04-02 Dragana Cvetković-Ilić, Oskar Maria Baksalary, Honglin Zou
An extensive matrix class over a complex Banach algebra is considered from the point of view of its quasinilpontency, nilpotency, as well as Drazin and generalized Drazin invertibilities. The matrices belonging to the class are obtained by alterations of a \(2 \times 2\) anti-triangular matrix with one undetermined entry, and the general expression characterizing the class involves powers of the anti-triangular
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A new commutativity property of exceptional orthogonal polynomials RACSAM (IF 2.9) Pub Date : 2024-03-29 M. M. Castro, F. A. Grünbaum
We exhibit three examples showing that the “time-and-band limiting” commutative property found and exploited by D. Slepian, H. Landau and H. Pollak at Bell Labs in the 1960s, and independently by M. Mehta and later by C. Tracy and H. Widom in Random matrix theory, holds for exceptional orthogonal polynomials. The property in question is the existence of local operators with simple spectrum that commute
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Orlicz geominimal surface areas RACSAM (IF 2.9) Pub Date : 2024-03-28 Chang-Jian Zhao
The main purpose of the present article is to introduce a new concept and call it Orlicz mixed geominimal surface area \(G_{\varphi }(K_{1},\ldots ,K_{n})\) of n convex bodies \(K_{1},\ldots ,K_{n}\), which obeys classical basic properties. The new affine geometric quantity in special case yields Petty’s geominimal surface area G(K), Lutwak’s p-geominimal surface area \(G_{p}(K)\) and the newly established
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Spectral transformations and second kind polynomials associated with a hermitian linear functional RACSAM (IF 2.9) Pub Date : 2024-03-25 Juan Carlos García-Ardila, Francisco Marcellán
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Some non-Riemannian curvature properties of the new class of $$(\alpha , \beta )$$ -metrics RACSAM (IF 2.9) Pub Date : 2024-03-24 Jila Majidi, Akbar Tayebi, Ali Haji-Badali
In this paper, we study some important non-Riemannian curvature properties of the new class of \( (\alpha ,\beta ) \)-metrics introduced by Pişcoran–Mishra in Finsler geometry. We prove that this class of Finsler metrics are Landsbergian if and only if they are weakly Landsbergian if and only if they are Berwaldian. Then, we show that this class of Finsler metrics has vanishing \(\Xi \)-curvature if
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On the set of functions that vanish at infinity and have a unique maximum RACSAM (IF 2.9) Pub Date : 2024-03-23 G. Araújo, A. Barbosa
In this paper, we show that the set of continuous functions defined on \({\mathbb {R}}^n\) that approach zero at infinity and attain their maximum at precisely one (and only one) point is n-lineable but not \((n+2)\)-lineable. This result complements some recent published works on an open question originally posed by Vladimir I. Gurariy (1935–2005) in 2003.
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A new paradigm in the logistic and similar maps: time stepping schemes RACSAM (IF 2.9) Pub Date : 2024-03-23 J. Alberto Conejero, Òscar Garibo-i-Orts, Carlos Lizama
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Helicoidal minimal surfaces in the 3-sphere: an approach via spherical curves RACSAM (IF 2.9) Pub Date : 2024-03-23
Abstract We prove an existence and uniqueness theorem about spherical helicoidal (in particular, rotational) surfaces with prescribed mean or Gaussian curvature in terms of a continuous function depending on the distance to its axis. As an application in the case of vanishing mean curvature, it is shown that the well-known conjugation between the belicoid and the catenoid in Euclidean three-space extends
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An analysis on the optimal feedback control for Caputo fractional neutral evolution systems in Banach spaces RACSAM (IF 2.9) Pub Date : 2024-03-22 S. Vivek, V. Vijayakumar
This paper focuses on optimal feedback control for a system involving neutral fractional equations in a Banach space. First, our investigation centers on establishing the existence of a mild solution for the given control system. We derive feasible pairs by using the Filippov theorem and the Cesari property. Furthermore, optimal feedback control pairs are introduced based on some sufficient conditions
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The reduction theorem for algebras of one-sided subshifts over arbitrary alphabets RACSAM (IF 2.9) Pub Date : 2024-03-21 Dirceu Bagio, Cristóbal Gil Canto, Daniel Gonçalves, Danilo Royer
Let R be a commutative unital ring, \({ \textsf {X}}\) a subshift, and \({\widetilde{{\mathcal {A}}}}_R({ \textsf {X}})\) the corresponding unital subshift algebra. We establish the reduction theorem for \({\widetilde{{\mathcal {A}}}}_R({ \textsf {X}})\). As a consequence, we obtain a Cuntz–Krieger uniqueness theorem for \({\widetilde{{\mathcal {A}}}}_R({ \textsf {X}})\) and we show that \({\widetilde{{\mathcal
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Weakly web-compact Banach spaces C(X), and $$Lip_0(M)$$ , $$\mathcal {F}(M)$$ over metric spaces M RACSAM (IF 2.9) Pub Date : 2024-03-21 Jerzy Ka̧kol
The class of web-compact spaces (in sense of Orihuela), which encompasses a number of spaces, like Lindelöf \(\Sigma \)-spaces (called also countably determined), Quasi-Suslin spaces, separable spaces, etc., applies to distinguish a class of weakly web-compact Banach spaces E whose dual unit ball is weak\(^{*}\)-sequentially compact, consequently Banach spaces without quotients isomorphic to \(\ell
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A characterization of the rate of approximation of Kantorovich sampling operators in variable exponent Lebesgue spaces RACSAM (IF 2.9) Pub Date : 2024-03-21 Borislav R. Draganov
We establish a direct and a matching two-term converse estimate by a K-functional and a modulus of smoothness for the rate of approximation by generalized Kantorovich sampling operators in variable exponent Lebesgue spaces. They yield the saturation property and class of these operators. We also prove a Voronovskaya-type estimate.
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Cofiniteness of top local cohomology modules RACSAM (IF 2.9) Pub Date : 2024-03-14
Abstract Let R be a commutative Noetherian ring with non-zero identity, \(\mathfrak {a}\) an ideal of R, M a finitely generated R-module with finite Krull dimension d, and n a non-negative integer. In this paper, we prove that the top local cohomology module \({\text {H}}^{d-n}_{\mathfrak {a}}(M)\) is an \(({\text {FD}}_{
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Ellis enveloping semigroups in real closed fields RACSAM (IF 2.9) Pub Date : 2024-03-13 Elías Baro, Daniel Palacín
We introduce the Boolean algebra of d-semialgebraic (more generally, d-definable) sets and prove that its Stone space is naturally isomorphic to the Ellis enveloping semigroup of the Stone space of the Boolean algebra of semialgebraic (definable) sets. For definably connected o-minimal groups, we prove that this family agrees with the one of externally definable sets in the one-dimensional case. Nonetheless
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A geometric Jordan decomposition theorem RACSAM (IF 2.9) Pub Date : 2024-03-11
Abstract For a compact convex set K, let A(K) denote the space of real-valued affine continuous functions, equipped with the supremum norm. For a closed subspace \(X \subset A(K)\) we give sufficient conditions, so that the weak \(^*\) closure of the set of extreme points of the dual unit ball has a decomposition in terms of ‘positive’ and ‘negative’ parts. We give several applications of these ideas
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New bounds for a generalized logarithmic mean and Heinz mean RACSAM (IF 2.9) Pub Date : 2024-03-10 Jiahua Ding, Ling Zhu
In this paper, by using the monotone form of L’Hospital’s rule and a criterion for the monotonicity of quotient of two power series we present some sharp bounds for a generalized logarithmic mean and Heinz mean by weighted means of harmonic mean, geometric mean, arithmetic mean, two power means \(M_{1/2}(a,b)\) and \(M_{2}(a,b)\). Operator versions of these inequalities are obtained except for those
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$$L^\infty $$ a-priori estimates for subcritical p-laplacian equations with a Carathéodory non-linearity RACSAM (IF 2.9) Pub Date : 2024-03-10
Abstract Let us consider a quasi-linear boundary value problem \( -\Delta _p u= f(x,u),\) in \(\Omega ,\) with Dirichlet boundary conditions, where \(\Omega \subset \mathbb {R}^N \) , with \(p0\) there exists a constant \(C_\varepsilon >0\) such that for any solution \(u\in H^1_0(\Omega )\) , the following holds $$\begin{aligned} \Big [\log \big (e+\Vert u\Vert _{\infty }\big )\Big ]^\alpha \le C_\varepsilon
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A Reilly type integral inequality for the p-Laplacian and applications to submanifolds of the unit sphere RACSAM (IF 2.9) Pub Date : 2024-03-08 Fábio R. dos Santos, Matheus N. Soares
An integral inequality for the compact (with or without boundary) submanifolds in the unit sphere with constant scalar curvature is established. Through this result, a characterization of totally geodesic spheres is obtained.
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Modes of convergence of random variables and algebraic genericity RACSAM (IF 2.9) Pub Date : 2024-02-24 G. Araújo, M. Fenoy, J. Fernández-Sánchez, J. López-Salazar, J. B. Seoane-Sepúlveda, J. M. Vecina
Important probabilistic problems require to find the limit of a sequence of random variables. However, this limit can be understood in different ways and various kinds of convergence can be defined. Among the many types of convergence of sequences of random variables, we can highlight, for example, that convergence in \(L^p\)-sense implies convergence in probability, which, in turn, implies convergence
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Some variations of the Banach-Mazur game RACSAM (IF 2.9) Pub Date : 2024-02-23
Abstract The classical Banach-Mazur game is directly related to the Baire property and the property of being a productively Baire space. In this paper, we discuss two variations of this classic game that are even more related to these properties.
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Trigonometric background multivariate smooth trigonometric singular integrals approximations RACSAM (IF 2.9) Pub Date : 2024-02-22 George A. Anastassiou
In this article we apply the uniform and \(L_{p}\), \(1\le p<\infty \) approximation properties of general smooth multivariate singular integral operators over \({\mathbb {R}}^{N}\), \(N\ge 1\). It is a trigonometric based approach with detailed applications to the corresponding smooth multivariate trigonometric singular integral operators. The results are quantitative via Jackson type inequalities
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Solution theory to semilinear stochastic equations of Schrödinger type on curved spaces I: operators with uniformly bounded coefficients RACSAM (IF 2.9) Pub Date : 2024-02-16
Abstract We study the Cauchy problem for Schrödinger type stochastic semilinear partial differential equations with uniformly bounded variable coefficients, depending on the space variables. We give conditions on the coefficients, on the drift and diffusion terms, on the Cauchy data, and on the spectral measure associated with the noise, such that the Cauchy problem admits a unique function-valued
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Sufficiency of weighted jets using Paunescu’s singular metric RACSAM (IF 2.9) Pub Date : 2024-02-05
Abstract In this work we consider the Paunescu’s singular metric in the source to investigate the bi-Lipschitz and differential sufficiency in the set of weighted jets of map germs with a fixed weighted degree. This approach was motivated by the works of Paunescu, who investigated the V-sufficiency from the weighted point of view considering this metric in the source. Here we show a criterion for the
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On the determination of p-Frobenius and related numbers using the p-Apéry set RACSAM (IF 2.9) Pub Date : 2024-02-03 Takao Komatsu
In this paper, we give convenient formulas in order to obtain explicit expressions of a generalized Frobenius number called the p-Frobenius number as well as its related values. Here, for a non-negative integer p, the p-Frobenius number is the largest integer whose number of solutions of the linear diophantine equation in terms of positive integers \(a_1,a_2,\ldots ,a_k\) with \(\gcd (a_1,a_2,\ldots
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Generating functions for polynomials derived from central moments involving bernstein basis functions and their applications RACSAM (IF 2.9) Pub Date : 2024-02-02 Ayse Yilmaz Ceylan, Yilmaz Simsek
The main objective of this article is to construct generating functions for central moments involving Bernstein basis functions. We give some alternating generating functions of these functions. We also give derivative formulas and a recurrence relation of central moments with the help of their generating functions. We also establish new relations between combinatorial numbers and polynomials, and
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Monotonicity and convexity (concavity) properties for zero-balanced hypergeometric function RACSAM (IF 2.9) Pub Date : 2024-01-31 Tie-Hong Zhao, Miao-Kun Wang
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Densifiability in hyperspaces RACSAM (IF 2.9) Pub Date : 2024-01-31 E. López-Pezoa, G. Mora, D. A. Redtwitz
The densifiability of a metric space (X, d) is the susceptibility of being filled by Peano continua. In the present paper we introduce the notion of densifiability on the hyperspace obtained from a determined collection of subsets of a metric space (X, d) endowed with a metric structure. Concretely, by using two theorems of Borsuk-Mazurkiewicz and Michael, we show that if the space (X, d) is a continuum
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Seiberg–Witten differentials on the Hitchin base RACSAM (IF 2.9) Pub Date : 2024-01-29 Ugo Bruzzo, Peter Dalakov
In this note we describe explicitly, in terms of Lie theory and cameral data, the covariant (Gauss–Manin) derivative of the Seiberg–Witten differential defined on the weight-one variation of Hodge structures that exists on a Zariski open subset of the base of the Hitchin fibration.
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Differential gradient estimates for nonlinear parabolic equations under integral Ricci curvature bounds RACSAM (IF 2.9) Pub Date : 2024-01-29 Shahroud Azami
Let \((M^{n},g)\) be a complete Riemannian manifold. We prove a space-time gradient estimates for positive solutions of nonlinear parabolic equations $$\begin{aligned} \partial _{t}u(x,t)=\Delta u(x,t)-p(x,t)A(u(x,t))-q(x,t) ( u(x,t))^{a+1}, \end{aligned}$$ on geodesic balls B(o, r) in M with \(0\frac{n}{2}\) when integral Ricci curvature k(p, 1) is small enough. By integrating the gradient estimates
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Helix surfaces for Berger-like metrics on the anti-de Sitter space RACSAM (IF 2.9) Pub Date : 2024-01-29 Giovanni Calvaruso, Irene I. Onnis, Lorenzo Pellegrino, Daria Uccheddu
We consider the Anti-de Sitter space \(\mathbb {H}^3_1\) equipped with Berger-like metrics, that deform the standard metric of \(\mathbb {H}^3_1\) in the direction of the hyperbolic Hopf vector field. Helix surfaces are the ones forming a constant angle with such vector field. After proving that these surfaces have (any) constant Gaussian curvature, we achieve their explicit local description in terms
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On polynomial representation by U-numbers RACSAM (IF 2.9) Pub Date : 2024-01-29
Abstract Let n be a positive integer and let \(P(x,y)\in \mathbb {Z}[x,y]\) be a non-constant polynomial. In this paper, we prove that every S- and T-number (under some technical conditions) can be written in the form \(P(\sigma , \tau )\) for uncountable many pairs \((\sigma , \tau )\) of \(U_n\) -numbers.
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Hall classes of groups RACSAM (IF 2.9) Pub Date : 2024-01-18
Abstract In 1958, Philip Hall (Ill J Math 2:787–801, 1958) proved that if a group G has a nilpotent normal subgroup N such that \(G/N'\) is nilpotent, then G is nilpotent. The scope of Hall’s nilpotency criterion is not restricted to group theory, and in fact similar statements hold for Lie algebras and more generally for algebraically coherent semiabelian categories (see Chao in Math Z 103:40–42,
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The isomorphism problem for basic modules and the divisibility profile of the algebra of polynomials RACSAM (IF 2.9) Pub Date : 2024-01-16 P. Aydoğdu, C. A. Arellano, S. R. López-Permouth, R. Muhammad, M. Zailaee
While mutual congeniality of bases is known to guarantee that basic modules from so-related bases are isomorphic, the question of what can be said about isomorphism of basic modules in general has remained open. We show that, for some algebras, basic modules may be non-isomorphic. We also show that it is possible, for some algebras, for all basic modules to be isomorphic, regardless of congeniality
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On structures of normal forms of complex points of small $${\mathcal {C}}^{2}$$ -perturbations of real 4-manifolds embedded in a complex 3-manifold RACSAM (IF 2.9) Pub Date : 2024-01-16 Tadej Starčič
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On zeros of the regular power series of a quaternionic variable RACSAM (IF 2.9) Pub Date : 2024-01-11 Gradimir V. Milovanović, Abdullah Mir
Using tools from the newly developed theory of regular functions and polynomials with quaternionic coefficients located on only one side of the variable, we derive zero-free regions for the related subclass of regular power series and obtain discs that are not centered at the origin, containing all the zeros of these polynomials. The results obtained for this particular subclass of regular functions
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Short $$(\textbf{SL}_2\times \textbf{SL}_2)$$ -structures on Lie algebras RACSAM (IF 2.9) Pub Date : 2024-01-06 Patricia D. Beites, Alejandra S. Córdova-Martínez, Isabel Cunha, Alberto Elduque
\(\textbf{S}\)-structures on Lie algebras, introduced by Vinberg, represent a broad generalization of the notion of gradings by abelian groups. Gradings by, not necessarily reduced, root systems provide many examples of natural \(\textbf{S}\)-structures. Here we deal with a situation not covered by these gradings: the short \((\textbf{SL}_2\times \textbf{SL}_2)\)-structures, where the reductive group
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Directed sets of topology: Tukey representation and rejection RACSAM (IF 2.9) Pub Date : 2024-01-05 Ziqin Feng, Paul Gartside
Every directed set is Tukey equivalent to (a) the family of all compact subsets, ordered by inclusion, of a (locally compact) space, to (b) a neighborhood filter, ordered by reverse inclusion, of a point (of a compact space, and of a topological group), and to (c) the universal uniformity, ordered by reverse inclusion, of a space. Two directed sets are Tukey equivalent if they are cofinally equivalent
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Existence and stability of invariant/periodic measures of lattice reversible Selkov systems driven by locally Lipschitz noise RACSAM (IF 2.9) Pub Date : 2024-01-04 Yan Wang, Chunxiao Guo, Yunshun Wu, Renhai Wang
This article is concerned with the existence and stability of invariant or periodic probability measures for a wide class of lattice reversible Selkov systems with coupled nonlinear terms of polynomial growth of arbitrary order defined on the entire integer set \(\mathbb {Z}\) driven by locally Lipschitz noise. We first formulate the stochastic lattice equations to an abstract system defined in the
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Hamiltonian systems involving exponential growth in $${\mathbb {R}}^{2}$$ with general nonlinearities RACSAM (IF 2.9) Pub Date : 2024-01-04 Uberlandio B. Severo, Manassés de Souza, Marta Menezes
In this work, we establish the existence of ground state solution for Hamiltonian systems of the form $$\begin{aligned} \left\{ \begin{aligned} -\Delta u + V(x)u = H_v(x,u,v), \quad x \in {\mathbb {R}}^2, \\ -\Delta v + V(x)v = H_u(x,u,v), \quad x \in {\mathbb {R}}^2, \end{aligned} \right. \end{aligned}$$ where \(V \in C({\mathbb {R}}^2, (0, \infty ))\) and \(H \in C^1({\mathbb {R}}^2 \times {\mathbb
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The m-weak core inverse RACSAM (IF 2.9) Pub Date : 2023-12-23 D. E. Ferreyra, Saroj B. Malik
Since the day the core inverse was known in a paper of Bakasarly and Trenkler, it has been widely researched. So far, there are four generalizations of this inverse for the case of matrices of an arbitrary index, namely, the BT inverse, the DMP inverse, the core-EP inverse and the WC inverse. In this paper we introduce a new type of generalized inverse for a matrix of an arbitrary index to be called
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Sharp sufficient conditions for mean convergence of the maximal partial sums of dependent random variables with general norming sequences RACSAM (IF 2.9) Pub Date : 2023-12-22 Lê Vǎn Thành
This paper provides sharp sufficient conditions for mean convergence of the maximal partial sums from triangular arrays of dependent random variables with general norming sequences. As an application, we use this result to give a positive answer to an open question in [Test 32(1):74–106, 2023] concerning mean convergence for the maximal partial sums under regularly varying moment conditions. The techniques
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Strongly Einstein real hypersurfaces in $${\mathbb {C}}P^2$$ and $${\mathbb {C}}H^2$$ RACSAM (IF 2.9) Pub Date : 2023-12-14 Yaning Wang, Yingdong Zhang
In this paper, we prove that a real hypersurface in \({\mathbb {C}}P^2(c)\) and \({\mathbb {C}}H^2(c)\) is strongly Einstein if and only if it is locally congruent to a geodesic sphere with radius \(d=2\ln (\sqrt{2}+1)/\sqrt{-c}\) in \({\mathbb {C}}H^2(c)\). This improves a resent paper by the present authors Wang and Zhang (Weakly Einstein real hypersurfaces in \({\mathbb {C}}P^2\) and \({\mathbb
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Some q-supercongruences from squares of basic hypergeometric series RACSAM (IF 2.9) Pub Date : 2023-12-08 Hanfei Song, Chun Wang
Inspired by the recent work of El Bachraoui and Guo-Li, we establish several q-supercongruences on the truncated forms of squares of basic hypergeometric series modulo the cube and the fourth power of a cyclotomic polynomial. Our proofs heavily rely on the creative microscoping method devised by Guo and Zudilin, a lemma due to El Bachraoui and the Chinese remainder theorem for coprime polynomials.
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Bivariate generalized Kantorovich-type exponential sampling series RACSAM (IF 2.9) Pub Date : 2023-12-08 Tuncer Acar, Abdulkadir Eke, Sadettin Kursun
In this paper, we introduce a family generalized Kantorovich-type exponential sampling operators of bivariate functions by using the bivariate Mellin-Gauss-Weierstrass operator. Approximation behaviour of the series is established at continuity points of log-uniformly continuous functions. A rate of convergence of the family of operators is presented by means of logarithmic modulus of continuity and