Adjunctions for exceptions
  An algebraic method is used to study the semantics of exceptions in computer languages. The exceptions form a computational effect, in the sense that there is an apparent mismatch between the syntax of exceptions and their intended semantics. We solve this apparent contradiction by efining a logic for exceptions with a proof system which is close to their syntax and where their intended semantics can be seen as a model. This requires a robust framework for logics and their morphisms, which is provided by categorical tools relying on adjunctions, fractions and limit sketches. 
Jean-Guillaume Dumas (LJK), Dominique Duval (LJK), Laurent Fousse   (LJK), Jean-Claude Reynaud (RC)
cs.LO math.CT