•  63
    Full classical S5 in natural deduction with weak normalization
    with Lilia Ramalho Martins
    Annals of Pure and Applied Logic 152 (1): 132-147. 2008.
    Natural deduction systems for classical, intuitionistic and modal logics were deeply investigated by Prawitz [D. Prawitz, Natural Deduction: A Proof-theoretical Study, in: Stockholm Studies in Philosophy, vol. 3, Almqvist and Wiksell, Stockholm, 1965. Reprinted at: Dover Publications, Dover Books on Mathematics, 2006] from a proof-theoretical perspective. Prawitz proved weak normalization for classical logic only for a language without logical or, there exists and with a restricted application o…Read more
  •  34
    Expressiveness and definability in circumscription
    with Francicleber Martins Ferreira
    Manuscrito 34 (1): 233-266. 2011.
    We investigate expressiveness and definability issues with respect to minimal models, particularly in the scope of Circumscription. First, we give a proof of the failure of the Löwenheim-Skolem Theorem for Circumscription. Then we show that, if the class of P; Z-minimal models of a first-order sentence is Δ-elementary, then it is elementary. That is, whenever the circumscription of a first-order sentence is equivalent to a first-order theory, then it is equivalent to a finitely axiomatizable one…Read more
  •  18
    Invisible cities: utopian spaces or imaginary places?
    Archai: Revista de Estudos Sobre as Origens Do Pensamento Ocidental 21 123-152. 2017.
  •  17
    Natural Deduction and Weak Normalization for Full Linear Logic
    with Lilia Martins
    Logic Journal of the IGPL 12 (6): 601-625. 2004.
    We review five recent works [1, 2, 9, 15, 16] which present natural deduction systems for linear logic, or for fragments of that logic, and introduce a new single-conclusion natural deduction system for first-order classical linear logic named NDLL. Moreover, we demonstrate the equivalence between the NDLL system and Girard's linear sequent calculus, and prove the weak normalization theorem and its usual companion: the subformula principle for normal deductions in NDLL.NDLL gives rules for the w…Read more
  •  17
    The notion of the least fixed point of an operator is widely applied in computer science as, for instance, in the context of query languages for relational databases. Some extensions of first-order classical logic with fixed point operators, as the least fixed point logic , were proposed to deal with problems related to the expressivity of FOL. LFP captures the complexity class PTIME over the class of finite ordered structures. The descriptive characterization of computational classes is a centr…Read more
  •  15
    A angústia de viver na cidade
    Bakhtiniana 10 (1): 156-175. 2015.
  •  12
    Word order change (edited book)
    with Adriana Cardoso
    Oxford University Press. 2018.
    This volume explores word order change within the framework of diachronic generative syntax and offers new insights into word order, syntactic movement, and related phenomena. It draws on data from a wide range of languages including Sanskrit, Tocharian, Portuguese, Irish, Hungarian and Coptic Egyptian.
  •  12
    On Minimal Models
    with Francicleber Ferreira
    Logic Journal of the IGPL 15 (5-6): 503-526. 2007.
    We investigate some logics which use the concept of minimal models in their definition. Minimal objects are widely used in Logic and Computer Science. They are applied in the context of Inductive Definitions, Logic Programming and Artificial Intelligence. An example of logic which uses this concept is the MIN logic due to van Benthem [20]. He shows that MIN is equivalent to the Least Fixed Point logic in expressive power. In [6], we extended MIN to the MIN Logic and proved it is equivalent to se…Read more
  •  11
    Invisible cities: utopian spaces or imaginary places?
    Archai: Revista de Estudos Sobre as Origens Do Pensamento Ocidental 22. 2018.
    Like Raphael Hythloday, Marco Polo narrated his journey to Kublai Khan, the Emperor of the Tartars, presenting a catalogue of places and a cartography of 55 cities. The magic realism of Italo Calvino, the lush and synaesthetic descriptions in Invisible Cities construct a symbolic imaginarium of utopian paradigms. The taxonomy of all these cities sheds light on their relationship to man: cities and memory, cities and desire, cities and signs, cities and eyes, cities and names, cities and the dead…Read more
  •  3
    Documento recente do Ministério da Educação aponta para a construção da identidade desse curso como sendo etapa final que compõe a educação básica e sinalizando a busca constante pela superação da dualidade considerada histórica entre formação geral e profissionalização. Entretanto, o mesmo documento reconhece que essa contradição ainda se faz presente na realidade educacional brasileira e, em alguns momentos, afirma a necessidade de uma educação integrada e em outros reforça a profissionalizaçã…Read more