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We describe Richardson's functor from the Diophantine equations and Diophan-tine problems into elementary real-valued functions and problems. We then derive a general undecidability and incompleteness result for elementary functions within ZFC set theory, and apply it to some problems in Hamiltonian mechanics and dynamical systems theory. Our examples deal… (More)

Artificial neural networks and fuzzy systems, have gradually established themselves as a popular tool in approximating complicated nonlinear systems and time series forecasting. This paper investigates the hypothesis that the nonlinear mathematical models of multi-layer perceptron and radial basis function neural networks and the Takagi–Sugeno (TS) fuzzy… (More)

- GALOIS THEORY, NEWTON C. A. DA COSTA, OTÁVIO BUENO, José Sebastião
- 2011

This paper is a historical companion to a previous one, in which it was studied the so-called abstract Galois theory as formulated by the Portuguese mathematician José Sebastião e Silva (see da Costa, Rodrigues (2007)). Our purpose is to present some applications of abstract Galois theory to higher-order model theory, to discuss Silva's notion of… (More)

Let us consider informally a theory T (deductive system). We say that T is trivial (or overcomplete) if all formulas of T are theorems of T ; otherwise, we say that T is non-trivial (or not overcomplete). T is inconsistent if it has a negation symbol and there are, at least, two theorems of T such that one is the negation of the other; if this is not the… (More)

- Newton Da Costa, Marco Goulart, Cesar Cupertino, Jurandir Macedo, Sergio Da Silva
- 2015

JEL classification: G11 G14 Keywords: Disposition effect Investor experience Artificial stock market Framed field experiment a b s t r a c t We examine whether investing experience can dampen the disposition effect, that is, the fact that investors seem to hold on to their losing stocks to a greater extent than they hold on to their winning stocks. To do… (More)

- Ricardo P. Câmara Leal, Newton C. A. da Costa, Ricardo P. Câmara
- 2003

Palavras-chaves: mercados emergentes; integração versus segmentação; modelos de precificação internacionais. A A A A ABSTRACT BSTRACT BSTRACT BSTRACT BSTRACT Many recent works have presented evidences about the existence of links between the stock markets of Brazil and Argentina. However the existence of links between two markets does not mean that they are… (More)

We argue that the Robertson-Walker's Universe is a zero-energy stable one, even though it may possess a rotational state besides expansion.

A lemma on a total function defined over the Baker–Gill–Solovay set of polynomial Turing machines. Abstract We prove here a lemma that connects some properties of the so–called " counterexample function " to the P = N P conjecture over the Baker– Gill–Solovay set of polynomial Turing machines to the behavior of the same function " at large, " over the set… (More)

A A A A ABSTRACT BSTRACT BSTRACT BSTRACT BSTRACT This work investigates mutual fund performance through data envelopment analysis. The data envelopment analysis has shown to be a powerful tool in the evaluation of investment performance when investor's expected utility function contains multiple attributes. Besides the traditional attributes risk and return… (More)

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