Adame-Carrillo, David Gaset, Jordi Román-Roy, Narciso
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
In general, the system of 2nd-order partial differential equations made of the Euler–Lagrange equations of classical field theories are not compatible for singular Lagrangians. This is the so-called second-order problem. The first aim of this work is to develop a fully geometric constraint algorithm which allows us to find a submanifold where the E...
Dinčić, Nebojša Č. Djordjević, Bogdan D.
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
In this paper we analyze isolated and connected points of the solution set to the Yang–Baxter-like matrix equation AXA=XAX\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}...
Toledo, F. J.
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
The objective of this paper is to provide the exact sets of initial data ensuring the convergence or divergence of a special class of real towers of powers and logarithms. All the terms forming these towers have a common value except the cusp element, that is indeed the initial data of the sequences defining the towers. The results obtained will be...
Fernández-Sánchez, J. Maghsoudi, S. Rodríguez-Vidanes, D. L. Seoane-Sepúlveda, J. B.
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
In this paper, we show new results and improvements of the non-Archimedean counterpart of classical analysis in the theory of lineability. Besides analyzing the algebraic genericity of sets of functions having properties regarding continuity, discontinuity, Lipschitzianity, differentiability and analyticity, we also study the lineability of sets of...
Yang, Jie
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
Let (Σ,g)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(\Sigma ,g)$$\end{document} be a closed Riemann surface, G be a finite isometric group acting on (Σ,g)\document...
Ferreyra, D. E. Malik, Saroj B.
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
The purpose of the present work is to introduce the concept of relative EP matrix of a rectangular matrix relative to a partial isometry (or, in short, T-EP matrix) hitherto unknown. We extend various basic results on EP matrices and we study the relationship between T-hermitian, T-normal and T-EP matrices. The main theorems of this paper consist i...
Gal, Sorin G. Niculescu, Constantin P.
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
In this paper we prove Korovkin type theorems for sequences of sublinear, monotone and weak additive operators acting on function spaces C(X), where X is a compact or a locally compact metric space. Our results are illustrated by a series of examples.
Wu, Cang Chen, Jianlong
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
We study the left version of core inverses in ∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$*$$\end{document}-rings. An example is given to show that there exists a ...
Srivastava, H. M. Shah, Firdous A. Teali, Aajaz A.
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
The special affine Fourier transform is a promising tool for analyzing transient signals with more degrees of freedom via a chirp-like basis. In this article, our goal is to introduce a novel quaternion-valued short-time special affine Fourier transform in the context of two-dimensional quaternion-valued signals. In addition to studying all fundame...
Demirci, Kamil Dirik, Fadime Yıldız, Sevda
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Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas
In this study, we define a new type of convergence using the notions of statistical convergence in the sense of the power series method and equi-statistical convergence then, we give an example that supports this new definition and after that we use it to prove a Korovkin-type approximation theorem. This theorem is a non-trivial generalization of K...
