This essay argues that Emil Lederer formulated his research agenda and his main theses in close theoretical contact with the conceptual framework of other schools of thought, as represented by major scholars such as Joseph Schumpeter, Rudolf Hilferding and Mikhail Ivanovich Tugan-Baranowsky. The impact of technological progress on the economic system is a central theme in Lederer’s work, whereas its linkage to the market structure and more specifically to the emergence of monopolies is also shared by Hilferding. Moreover, Lederer argued that business cycles constitute an endogenous characteristic of capitalism and should not only be attributed to external shocks which disrupt an otherwise harmonious economic environment. In his major work Technical Progress and Unemployment (1938), Lederer argued that business cycles could arise from the disruptions created by innovations which are introduced discontinuously into the economic system, a thesis that is traditionally known to be of Schumpeterian inspiration. Hilferding and Tugan–Baranowsky delivered theories of economic fluctuations focusing on the role of disproportional growth between production sectors.

En su intervención en la VI Conferencia Internacional sobre Seguridad que se llevó a cabo el 26 y 27 de abril en la ciudad de Moscú, en Rusia, el ministro del Poder Popular para la Defensa, Vladimir Padrino López, manifestó su preocupación por el acuerdo de cooperación pactado entre Colombia y la Organización del Tratado del Atlántico Norte (OTAN) porque atenta contra la soberanía de Venezuela y países hermanos. Recordó que en Colombia existen siete bases militares estadounidenses, mientras el acuerdo con el pacto noratlántico se formalizó a finales de noviembre del pasado año.

En este ensayo se argumenta que la tesis estoica de la igualdad natural entre los seres humanos presupone una reconsideración radical de la noción de naturaleza, probablemente inspirada en el sofista Antifonte. Aunque los estoicos parecen considerar el naturalismo antifonteo, centrado en las facultades corpóreas, y reconocen la distinción clásica ‘convencional-natural’ aplicada a la diferencia entre griegos y bárbaros, desarrollan la tesis de la igualdad de naturaleza en dirección de una teoría de la justicia y la ley natural que supera la identidad de naturaleza entendida como necesidad corpórea. El autor sostiene que ese desarrollo se funda en la tesis estoica de la familiaridad.

Nícmer Evans 25/04/17. A lo largo de todos mis análisis como profesional de las Ciencias Políticas y de la Psicología Social, jamás había utilizado la categoría «guerra civil» para describir un escenario político y social en Venezuela, ciertamente cosa distinta a cuando he tenido que formular análisis descriptivos de Colombia. Pero hoy es distinto. Lo […]

Para la Cepal la pregunta era si la asociación con China, sustentada en la exportación de recursos naturales, se correspondía al tipo de desarrollo que requería nuestra región. ¿Se trataba de una asociación basada en el entrecruce de vínculos productivos, en la innovación tecnológica y en la incorporación de conocimiento? La respuesta era claramente negativa en la medida en que el 90% de las exportaciones regionales a China estaba compuestas por recursos naturales y el 88,5% de las importaciones provenientes de China eran manufacturas. Si algo demuestra la situación actual es que ser un gigante en recursos naturales equivale a ser un gigante de papel.

Almost two decades ago, Wattenberg published a paper with the title ‘Nonstandard Analysis and Constructivism?’ in which he speculates on a possible connection between Nonstandard Analysis and constructive mathematics. We study Wattenberg’s work in light of recent research on the aforementioned connection. On one hand, with only slight modification, some of Wattenberg’s theorems in Nonstandard Analysis are seen to yield effective and constructive theorems (not involving Nonstandard Analysis). On the other hand, we establish the incorrectness of some of Wattenberg’s (explicit and implicit) claims regarding the constructive status of the axioms Transfer and Standard Part of Nonstandard Analysis.

In the early twentieth century, L.E.J. Brouwer pioneered a new philosophy of mathematics, called intuitionism. Intuitionism was revolutionary in many respects but stands out -mathematically speaking- for its challenge of Hilbert’s formalist philosophy of mathematics and rejection of the law of excluded middle from the ‘classical’ logic used in mainstream mathematics. Out of intuitionism grew intuitionistic logic and the associated Brouwer-Heyting-Kolmogorov interpretation by which ‘there exists x’ intuitively means ‘an algorithm to compute x is given’. A number of schools of constructive mathematics were developed, inspired by Brouwer’s intuitionism and invariably based on intuitionistic logic, but with varying interpretations of what constitutes an algorithm. This paper deals with the dichotomy between constructive and non-constructive mathematics, or rather the absence of such an ‘excluded middle’.

Visibility algorithms are a family of geometric and ordering criteria by which a real-valued time series of N data is mapped into a graph of N nodes. This graph has been shown to often inherit in its topology non-trivial properties of the series structure, and can thus be seen as a combinatorial representation of a dynamical system. Here we explore in some detail the relation between visibility graphs and symbolic dynamics. To do that, we consider the degree sequence of horizontal visibility graphs generated by the one-parameter logistic map, for a range of values of the parameter for which the map shows chaotic behaviour. Numerically, we observe that in the chaotic region the block entropies of these sequences systematically converge to the Lyapunov exponent of the system. Via Pesin identity, this in turn suggests that these block entropies are converging to the Kolmogorov- Sinai entropy of the map, which ultimately suggests that the algorithm is implicitly and adaptively constructing phase space partitions which might have the generating property.

Graph polynomials are graph parameters invariant under graph isomorphisms which take values in a polynomial ring with a fixed finite number of indeterminates. We study graph polynomials from a model theoretic point of view. In this paper we distinguish between the graph theoretic (semantic) and the algebraic (syntactic) meaning of graph polynomials. We discuss how to represent and compare graph polynomials by their distinctive power. We introduce the class of graph polynomials definable using Second Order Logic which comprises virtually all examples of graph polynomials with a fixed finite set of indeterminates. Finally we show that the location of zeros and stability of graph polynomials is not a semantic property. The paper emphasizes a model theoretic view and gives a unified exposition of classical results in algebraic combinatorics together with new and some of our previously obtained results scattered in the graph theoretic literature.

Let G be the group Z d or the monoid N d where d is a positive integer. Let X be a subshift over G , i.e., a closed and shift-invariant subset of A G where A is a finite alphabet. We prove that the topological entropy of X is equal to the Hausdorff dimension of X and has a sharp characterization in terms of the Kolmogorov complexity of finite pieces of the orbits of X . In the version of this paper that has been published in Theory of Computing Systems, the proof of Lemma 4.3 contains a confusing typographical error. This version of the paper corrects that error.