2003: Volume 1
Intersection Type Systems and Logics Related to the Meyer-Routley System B+
13 pages. Published September 16, 2003
Some, but not all, closed terms of the lambda calculus have types; these types are exactly the theorems of intuitionistic implicational logic. An extension of these simple (→) types to intersection (or →∧) types allows all closed lambda terms to have types. The corresponding →∧ logic, related to the Meyer-Routley minimal logic B+ (without ∨), is weaker than the →∧ fragment of intuitionistic logic. In this paper we provide an introduction to the above work and also determine the →∧ logics that correspond to certain interesting subsystems of the full →∧ type theory.
Three Schools of Paraconsistency
14 pages. Published July 1, 2003
A logic is said to be paraconsistent if it does not allow everything to follow from contradictory premises. There are several approaches to paraconsistency. This paper is concerned with several philosophical positions on paraconsistency. In particular, it concerns three ‘schools’ of paraconsistency: Australian, Belgian and Brazilian. The Belgian and Brazilian schools have raised some objections to the dialetheism of the Australian school. I argue that the Australian school of paraconsistency need not be closed down on the basis of the Belgian and Brazilian schools’ objections. In the appendix of the paper, I also argue that the Brazilian school’s view of logic is not coherent.
Semantic Decision Procedures for Some Relevant Logics
24 pages. Published July 1, 2003
This paper proves decidability of a range of weak relevant logics using decision procedures based on the Routley-Meyer semantics. Logics are categorized as F-logics, for those proved decidable using a filtration method, and U-logics, for those proved decidable using a direct (unfiltered) method. Both of these methods are set out as reductio methods, in the style of Hughes and Cresswell. We also examine some extensions of the U-logics where the method fails and infinite sequences of worlds can be generated.
3 pages. Published July 1, 2003
The editorial explains why we have decided to launch the Journal.
Copyright © 2003, Philosophy Department, University of Melbourne.
Individual papers are copyright their authors.