9 found
Order:
  1.  24
    Foreword.Walter Carnielli, Edward Hermann Haeusler & Petrucio Viana - 2017 - Logic Journal of the IGPL 25 (4):381-386.
  2.  24
    Hybrid logics with Sahlqvist axioms.Balder Cate, Maarten Marx & Petrúcio Viana - 2005 - Logic Journal of the IGPL 13 (3):293-300.
    We show that every extension of the basic hybrid logic with modal Sahlqvist axioms is complete. As a corollary of our approach, we also obtain the Beth property for a large class of hybrid logics. Finally, we show that the new completeness result cannot be combined with the existing general completeness result for pure axioms.
    Direct download  
     
    Export citation  
     
    Bookmark   10 citations  
  3.  33
    On vague notions and modalities: a modular approach.Paulo Veloso, Sheila Veloso, Petrúcio Viana, Renata de Freitas & Mario Benevides - 2010 - Logic Journal of the IGPL 18 (3):381-402.
    Vague notions, such as ‘generally’, ‘rarely’, ‘often’, ‘almost always’, ‘a meaningful subset of a whole’, ‘most’, etc., occur often in ordinary language and in some branches of science. We introduce modal logical systems, with generalized operators, for the precise treatment of assertions involving some versions of such vague notions. We examine modal logics, constructed in a modular fashion, with generalized operators corresponding to some versions of ‘generally’ and ‘rarely’.
    Direct download  
     
    Export citation  
     
    Bookmark   2 citations  
  4. XVI Brazilian Logic Conference (EBL 2011).Walter Carnielli, Renata de Freitas & Petrucio Viana - 2012 - Bulletin of Symbolic Logic 18 (1):150-151.
    This is the report on the XVI BRAZILIAN LOGIC CONFERENCE (EBL 2011) held in Petrópolis, Rio de Janeiro, Brazil between May 9–13, 2011 published in The Bulletin of Symbolic Logic Volume 18, Number 1, March 2012. -/- The 16th Brazilian Logic Conference (EBL 2011) was held in Petro ́polis, from May 9th to 13th, 2011, at the Laboratório Nacional de Computação o Científica (LNCC). It was the sixteenth in a series of conferences that started in 1977 with the aim of (...)
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
  5. Diagrammatic Representation and Inference. 12th International Conference, Diagrams 2021, Virtual, September 28–30, 2021, Proceedings.Amrita Basu, Gem Stapleton, Sven Linker, Catherine Legg, Emmanuel Manalo & Petrucio Viana (eds.) - 2021 - Springer.
    This book constitutes the refereed proceedings of the 12th International Conference on the Theory and Application of Diagrams, Diagrams 2021, held virtually in September 2021. The 16 full papers and 25 short papers presented together with 16 posters were carefully reviewed and selected from 94 submissions. The papers are organized in the following topical sections: design of concrete diagrams; theory of diagrams; diagrams and mathematics; diagrams and logic; new representation systems; analysis of diagrams; diagrams and computation; cognitive analysis; diagrams as (...)
    Direct download  
     
    Export citation  
     
    Bookmark  
  6.  13
    On the (In)Dependence of the Peano Axioms for Natural Numbers.Márcia R. Cerioli, Hugo Nobrega, Guilherme Silveira & Petrucio Viana - 2021 - History and Philosophy of Logic 43 (1):51-69.
    We investigate two notions of independence— independence and complete independence—applied to the Peano axioms for the sequence of natural numbers. We review the results that, although they...
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark  
  7.  18
    On Positive Relational Calculi.Renata de Freitas, Paulo Veloso, Sheila Veloso & Petrucio Viana - 2007 - Logic Journal of the IGPL 15 (5-6):577-601.
    We discuss the question of inclusions between positive relational terms and some of its aspects, using the form of a dialogue. Two possible approaches to the problem are emphasized: natural deduction and graph manipulations. Both provide sound and complete calculi for proving the valid inclusions, supporting nice strategies to obtain proofs in normal form, but the latter appears to present several advantages, which are discussed.
    Direct download  
     
    Export citation  
     
    Bookmark   1 citation  
  8.  21
    Set Venn Diagrams Applied to Inclusions and Non-inclusions.Renata de Freitas & Petrucio Viana - 2015 - Journal of Logic, Language and Information 24 (4):457-485.
    In this work, formulas are inclusions \ and non-inclusions \ between Boolean terms \ and \. We present a set of rules through which one can transform a term t in a diagram \ and, consequently, each inclusion \ ) in an inclusion \ ) between diagrams. Also, by applying the rules just to the diagrams we are able to solve the problem of verifying if a formula \ is consequence of a, possibly empty, set \ of formulas taken as (...)
    Direct download (2 more)  
     
    Export citation  
     
    Bookmark  
  9.  49
    (1 other version)On fork arrow logic and its expressive power.Paulo A. S. Veloso, Renata P. de Freitas, Petrucio Viana, Mario Benevides & Sheila R. M. Veloso - 2007 - Journal of Philosophical Logic 36 (5):489 - 509.
    We compare fork arrow logic, an extension of arrow logic, and its natural first-order counterpart (the correspondence language) and show that both have the same expressive power. Arrow logic is a modal logic for reasoning about arrow structures, its expressive power is limited to a bounded fragment of first-order logic. Fork arrow logic is obtained by adding to arrow logic the fork modality (related to parallelism and synchronization). As a result, fork arrow logic attains the expressive power of its first-order (...)
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark