• Boolean negation and non-conservativity I: Relevant modal logics 

      Øgaard, Tore Fjetland (Journal article; Peer reviewed, 2020)
      Many relevant logics are conservatively extended by Boolean negation. Not all, however. This paper shows an acute form of non-conservativeness, namely that the Boolean-free fragment of the Boolean extension of a relevant ...
    • Boolean negation and non-conservativity II: The variable-sharing property 

      Øgaard, Tore Fjetland (Journal article; Peer reviewed, 2020)
      Many relevant logics are conservatively extended by Boolean negation. Not all, however. This paper shows an acute form of non-conservativeness, namely that the Boolean-free fragment of the Boolean extension of a relevant ...
    • Boolean negation and non-conservativity III: the Ackermann constant 

      Øgaard, Tore Fjetland (Journal article; Peer reviewed, 2020)
      It is known that many relevant logics can be conservatively extended by the truth constant known as the Ackermann constant. It is also known that many relevant logics can be conservatively extended by Boolean negation. ...
    • Confused Entailment 

      Øgaard, Tore Fjetland (Journal article; Peer reviewed, 2021)
      Priest argued in his paper Fusion and Confusion (Priest, 2015a) for a new concept of logical consequence over the relevant logic B, one where premises my be “confused” together. This paper develops Priest’s idea. Whereas ...
    • Farewell to Suppression-Freedom 

      Øgaard, Tore Fjetland (Journal article; Peer reviewed, 2020)
      Val Plumwood and Richard Sylvan argued from their joint paper The Semantics of First Degree Entailment (Routley and Routley in Noûs 6(4):335–359, 1972, https://doi.org/10.2307/2214309) and onward that the variable sharing ...
    • Non-Boolean classical relevant logics II: Classicality through truth-constants 

      Øgaard, Tore Fjetland (Journal article; Peer reviewed, 2021)
      This paper gives an account of Anderson and Belnap's selection criteria for an adequate theory of entailment. The criteria are grouped into three categories: criteria pertaining to modality, those pertaining to relevance, ...