ML and Extended Branching VASS

  • Conrad Cotton-BarrattEmail author
  • Andrzej S. Murawski
  • C. -H. Luke Ong
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10201)


We prove that the observational equivalence problem for a finitary fragment of ML is recursively equivalent to the reachability problem for extended branching vector addition systems with states (EBVASS). Our proof uses the fully abstract game semantics of the language. We introduce a new class of automata, VPCMA, as a representation of the game semantics. VPCMA are a version of class memory automata equipped with a visibly pushdown stack; they serve as a bridge enabling interreducibility of decision problems between the game semantics and EBVASS. The results of this paper complete our programme to give an automata classification of the ML types with respect to the observational equivalence problem for closed terms.


Visibility Condition Closure Property Initial Move Reachability Problem Closed Term 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We are grateful to the anonymous reviewers for numerous constructive suggestions and to Ranko Lazić for discussions on VASS.


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Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  • Conrad Cotton-Barratt
    • 1
    Email author
  • Andrzej S. Murawski
    • 2
  • C. -H. Luke Ong
    • 1
  1. 1.University of OxfordOxfordUK
  2. 2.University of WarwickCoventryUK

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