Experiments may not reveal their full import at the time that they are performed. The scientists who perform them usually are testing a specific hypothesis and quite often have specific expectations limiting the possible inferences that can be drawn from the experiment. Nonetheless, as Hacking has said, experiments have lives of their own. Those lives do not end with the initial report of the results and consequences of the experiment. Going back and rethinking the consequences of the experiment in a new context, theoretical or empirical, has great merit as a strategy for investigation and for scientific problem analysis. I apply this analysis to the interplay between Fizeau’s classic optical experiments and the building of special relativity. Einstein’s understanding of the problems facing classical electrodynamics and optics, in part, was informed by Fizeau’s 1851 experiments. However, between 1851 and 1905, Fizeau’s experiments were duplicated and reinterpreted by a succession of scientists, including Hertz, Lorentz, and Michelson

¿En qué consiste el método para construir modelos de la Teoría de conjuntos llamado “FORCING” que creó Cohen (1963-64) ? y ¿Cuál es su importancia en las Matemáticas contemporáneas?. “No es fácil explicar los detalles del trabajo de Cohen en pocas palabras y a no especialistas en lógica”.

U.S. President Donald Trump has long been an opponent of the nuclear deal with Iran. At the recent UN General Assembly, he called the agreement an embarrassment. After the administration certified that Iran was in compliance with the Joint Comprehensive Plan of Action (JCPOA) in July, Trump instructed a trusted group of advisors to build a case to not certify Iran’s compliance when the next deadline came due on October 15. With the new deadline approaching, Trump has three options. Continue to certify that the Iran is in compliance with its obligations under JCPOA, notify Congress that Iran is no longer in compliance, or notify Congress that remaining in the JCPOA is no longer in the national interest of the United States.

Complex networks have gained much attention from different areas of knowledge in recent years. Particularly, the structures and dynamics of such systems have attracted considerable interest. Complex networks may have characteristics of multifractality. In this study, we analyze fractal and multifractal properties of a novel network: the large scale economic network of payments of Estonia, where companies are represented by nodes and the payments done between companies are represented by links. We present a fractal scaling analysis and examine the multifractal behavior of this network by using a sandbox algorithm. Our results indicate the existence of multifractality in this network and consequently, the existence of multifractality in the Estonian economy. To the best of our knowledge, this is the first study that analyzes multifractality of a complex network of payments.

We survey the main ideas in the early history of the subjects on which Riemann worked and that led to some of his most important discoveries. The subjects discussed include the theory of functions of a complex variable, elliptic and Abelian integrals, the hypergeometric series, the zeta function, topology, differential geometry, integration, and the notion of space. We shall see that among Riemann’s predecessors in all these fields, one name occupies a prominent place, this is Leonhard Euler.

Es conocido que el método de forcing es una de las técnicas de construcción de modelos más importantes de la Teoría de conjuntos en la actualidad, siendo el mismo muy útil para investigar problemas de matemática y de fundamentos de la matemática. El objetivo del siguiente trabajo es estudiar tal método, describir algunas de sus aplicaciones y ofrecer una aproximación a sus fundamentos metamatemáticos. Se aspira que este texto sirva de apoyo para aprender dicho método.

We present a list of open questions in mathematical physics. After a historical introduction, a number of problems in a variety of different fields are discussed, with the intention of giving an overall impression of the current status of mathematical physics, particularly in the topical fields of classical general relativity, cosmology and the quantum realm. This list is motivated by the recent article proposing 42 fundamental questions (in physics) which must be answered on the road to full enlightenment. But paraphrasing a famous quote by the British football manager Bill Shankly, in response to the question of whether mathematics can answer the Ultimate Question of Life, the Universe, and Everything, mathematics is, of course, much more important than that.

El Teorema de indecidibilidad de Church es uno de los resultados meta-teóricos de mediados de la tercera década del siglo pasado, que junto a otros teoremas limitativos como los de Gödel y Tarski, han generado todo un sinfín de reflexiones y análisis tanto en el marco de las ciencias formales, esto es, la matemática, la lógica y la computación teórica, como fuera de ellas, en especial la filosofía de la matemática, la filosofía de la lógica y la filosofía de la mente. Nos proponemos, como propósito general del presente artículo, formular el Teorema de indecidibilidad de Church y presentar las ideas principales de su demostración. Para llevar a cabo el primer objetivo necesitamos introducir y explicar las nociones de función recursiva y la numeración de Gödel, que permitirán enunciar de manera formal y rigurosa el Teorema de Church.

Rafael Palacios 10/10/2017. América Latina aún no termina de dar señales suficientes sobre su verdadera capacidad para innovar. La innovación como imperativo del crecimiento económico aún no es concebida y mucho menos observable en la actuación del Estado. La innovación no se visibiliza como forma visionaria para orientar la política y la economía. Más bien, […]

Luis Fuenmayor Toro  Coordinador Nacional de “De Frente con Venezuela”  Las conversaciones en Dominicana y las habidas desde hace cierto tiempo para acá no son del mismo tenor de las anteriores. La realidad actual nacional e internacional ha presionado en forma implacable, en función de llegar a un acuerdo real y permanente entre las fuerzas […]