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An $n\times n$ matrix $C$ is said to be {\it centrosymmetric} if it satisfies the relation $JCJ=C$, where $J$ is the $n\times n$ counteridentity matrix. Centrosymmetric matrices have a rich eigenstructure that has been studied extensively in the literature. Many results for centrosymmetric matrices have been generalized to wider classes of matrices that arise in a wide variety of disciplines. In this paper, we obtain interesting spectral properties for nonnegative centrosymmetric matrices. We show how to change one single eigenvalue, two or three eigenvalues of an $n\times n$ nonnegative centrosymmetric matrix without changing any of the remaining eigenvalues neither nonnegativity nor the centrosymmetric structure. Moreover, our results allow partially answer some known questions given by Guo [11] and by Guo and Guo [12]. Our proofs generate algorithmic procedures that allow to compute a solution matrix., Comment: 23 pages

All graphs considered are simple and undirected. The Inverse Eigenvalue Problem of a Graph $G$ (IEP-G) aims to find all possible spectra for matrices whose $(i,j)-$entry, for $i\neq j$, is nonzero precisely when $i$ is adjacent to $j$. A cluster in a graph $G$ is a pair of vertex subsets $(C, S)$, where $C$ is a maximal set of cardinality $\vert C\vert\geq 2$ of independent vertices sharing the same set $S$ of $\vert S\vert$ neighbors. Let $G$ be a connected graph on $n$ vertices with a cluster $(C, S)$ and $H$ be a graph of order $\vert C\vert$. Let $G(H)$ be the connected graph obtained from $G$ and $H$ when the edges of $H$ are added to the edges of $G$ by identifying the vertices of $H$ with the vertices in $C$. In this paper, we construct a symmetric matrix with associated complete graph, which satisfies some interesting properties. This result is applied to obtain new sufficient conditions on the IEP-G, when $G$ is a graph of order $n$ having a clique of order $k$ and a cluster $(C,S)$, where $\vert C\vert=n-k$ and $\vert S\vert=r\leq k$, as well as, for the graph $G(K_{n-k})$, being $G$ as before. In particular, when $G$ is a graph obtained from $K_{n}$ by deleting a single edge $e_{k}\in E(K_{n})$, we establish a necessary and sufficient condition on the IEP-G. Several illustrative example are given. The constructive nature of our results generate algorithmic procedures that always allow one to compute a solution matrix., 17 pages, 6 figures

Yoruba dance is the result of a syncretic and intercultural process that emulates the contemporary scene. In this article, we propose an acting training that locates the needs identified by exponents of the gestual and psychophysical/intercultural formative slopes and channels them through yoruba dance as a structure and context, integrating the magical religious universe and the history of transculturation of an important part of artistic Latin American manifestations. In this way, our methodological proposal involves postulates of acting training in the Western tradition with the expressive ways in which African cultures persist in the Latin American tradition. This would generate a space of respect for our Latin American past and its syncretism. In short, the acting training proposed from the yoruba dance aims to provide the necessary interpretive tools to assume the stylistic and poetic diversity of the scene of our time from an ethical and holistic position. La danza yoruba es el resultado de un proceso sincrético e intercultural que emula a la escena contemporánea. En este artículo, proponemos un entrenamiento actoral que ubica las necesidades identificadas por exponentes de las vertientes formativas gestual y psicofísica/intercultural y las canaliza a través de la danza yoruba como estructura y contexto, integrando el universo mágico-religioso y la historia de transculturación de una parte importante de las manifestaciones artísticas latinoamericanas. De este modo, nuestra propuesta metodológica involucra una combinación de los postulados de la formación actoral en la tradición occidental con las formas expresivas de las culturas africanas que persisten en la tradición latinoamericana. Esto generaría un espacio de respeto por nuestro pasado latinoamericano y su sincretismo. En suma, el entrenamiento actoral propuesto a partir de la danza yoruba pretende brindar las herramientas interpretativas necesarias para asumir la diversidad estilística y poética de la escena de nuestro tiempo desde un posicionamiento ético y holístico.

This article shares a teaching experience in the teaching of corporal expression in the framework of virtuality. The methodological proposal and the exposed exercises reflect the imprint from which we had to rethink objectives and contents in body work from technological mediation and remote presence, which suggests a paradigm shift for teaching and learning processes from the University of Costa Rica. The proposal exposes a journey towards the appropriation of the body as an expressive tool for students of the third semester of the Dramatic Arts career, while also reflecting on the implications of the absence of the body-present in the teaching-learning processes. Este artículo comparte una experiencia docente en la enseñanza de la expresión corporal en el marco de la virtualidad. La propuesta metodológica y los ejercicios que se exponen reflejan la impronta a partir de la cual tuvimos que replantearnos objetivos y contenidos en el trabajo corporal a partir de la mediación tecnológica y la presencia remota, lo cual sugiere un cambio de paradigma para los procesos de enseñanza-aprendizaje de la Universidad de Costa Rica. La propuesta expone un recorrido hacia la apropiación del cuerpo como herramienta expresiva en estudiantes de tercer semestre de la carrera de Artes Dramáticas, a la vez que reflexiona sobre las implicaciones de la ausencia del cuerpo-presente en los procesos de enseñanza-aprendizaje.