A Labelled System for IPL with Variable Splitting

  • Roger Antonsen
  • Arild Waaler
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4603)


The paper introduces a free variable, labelled proof system for intuitionistic propositional logic with variable splitting. In this system proofs can be found without backtracking over rules by generating a single, uniform derivation. We prove soundness, introduce a construction that extracts finite countermodels from unprovable sequents, and formulate a branchwise termination condition. This is the first proof system for intuitionistic propositional logic that admits goal-directed search procedures without compromising proof lengths, compared to corresponding tableau calculi.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • Roger Antonsen
    • 1
  • Arild Waaler
    • 1
  1. 1.Department of Informatics, University of OsloNorway

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