Sección especial: Espacios, relaciones sociales y poder. Propuestas para estudiarlos Juan Manuel Tornello Notificaciones, reel, noticieros, streaming, tweets invaden permanentemente nuestra atención. Hay una saturación de datos, muchas veces contradictorios, donde se mezcla sin mucha jerarquía un muestrario de hechos relevantes e irrelevantes. Los algoritmos nos seccionan y seleccionan en función de preferencias.
We prove the undecidability of determining whether a Turing machine yields an eventually periodic trajectory. From this, we deduce the undecidability of orbit finiteness in the polynomial dynamical system on infinite tuples of integers.
In this note, we determine, by a disjunctive normal form theorem, which functions on the standard $n$-nuanced Łukasiewicz-Moisil algebra are representable by formulas and we show how this result may help in establishing the structure of the free algebras in this class.
If G is a closed Noetherian graph on a sigma-compact Polish space without an infinite clique, it is consistent with the choiceless set theory ZF+DC that G is countably chromatic and there is no Vitali set.
A classical theorem from measure theory that gives a sufficient condition for a multifunction to have a measurable selection is Kuratowski and Ryll-Nardzewski Selection Theorem. The aim of this paper is to show some generalizations of this result.
We isolate a new preservation class of Suslin forcings and prove several associated consistency results in the choiceless theory ZF+DC regarding countable chromatic numbers of various Borel hypergraphs.
It is shown that the resurrection axiom and the maximality principle may be consistently combined for various iterable forcing classes. The extent to which resurrection and maximality overlap is explored via the local maximality principle.
This paper is a continuation of Arai's paper on derivability conditions for Rosser provability predicates. We investigate the limitations of the second incompleteness theorem by constructing three different Rosser provability predicates satisfying several derivability conditions.
This paper is a sequel to [1] and considers definability in differential-henselian monotone fields with c-map and angular component map. We prove an Equivalence Theorem among whose consequences are a relative quantifier reduction and an NIP result.
Assuming the existence of a supercompact cardinal, we construct a model where, for some uncountable regular cardinal $κ$, there are no $Σ^1_1(κ)-κ-$mad families.
We prove that several versions of the Tietze extension theorem for functions with moduli of uniform continuity are equivalent to WKL_0 over RCA_0. This confirms a conjecture of Giusto and Simpson that was also phrased as a question in Montalbán's "Open questions in reverse mathematics."
We prove a classical theorem due to Legendre, about the existence of non trivial solutions of quadratic diophantine equations of the form $ax^2+by^2+cz^2=0$, in the weak fragment of Peano Arithmetic $IΔ_0+Ω_1$.
En este trabajo, realizado desde el interior del espacio conceptual conductista, se reflexiona, en primer lugar, sobre el papel de Skinner en relación con los diversos conductismos para, después, abordar la concepción skinneriana de la explicación científica, la lógica de la investigación y la construcción teórica. Posteriormente se analizan las innovaciones que, dentro de la teoría del condicionamiento, introdujo Skinner, destacando las ventajas que ello supuso así como los nuevos problemas que planteó a la teoría de la conducta. A continuación se realiza una aproximación a la contribución metodológica de Skinner –la operante libre– y se evalúa su impacto histórico sobre las prácticas de investigación psicológica. Se destaca también el interés skinneriano por el comportamiento humano y cómo sólo de forma analógica y muy parcialmente Skinner se acercó a su análisis experimental en el laboratorio; se resalta cómo el resto de su abordaje de la conducta humana puede caracterizarse como un análisis hermeneútico y de extensión definicional y teórica. En tal sentido se revisan, principalmente, sus concepciones sobre la conducta gobernada por reglas y la conducta verbal. Finalmente, se analiza la lógica del nacimiento y evolución de la tecnología conductual con base skinneriana, subrayando las restricciones que el paradigma del condicinamiento operante impuso a la metodología aplicada al ser extrapolado a situaciones sociales humanas.
This note answers the following question: Is it consistent that for an arbitrary tall summable ideal I_g there exists an I_g-ultrafilter which is not rapid? We show that assuming Martin's Axiom for σ-centered posets such ultrafilters exist for each tall summable ideal I_g.
We give a direct, detailed and relatively short proof of Shelah's theorem on club guessing sequences on $S^{μ^+}_μ$ (for any regular, uncountable cardinal $μ$).
We formulate and prove (in {\sf ZFC}) a strong coloring theorem which holds at successors of singular cardinals, and use it to answer several questions concerning Shelah's principle $Pr_1(μ^+,μ^+,μ^+,\cf(μ))$ for singular $μ$.