Unification and matching modulo nilpotence

  • Qing Guo
  • Paliath Narendran
  • D. A. Wolfram
Session 4A
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1104)


We consider equational unification and matching problems where the equational theory contains a nilpotent function, i.e., a function f satisfying f(x,x)=0 where 0 is a constant. Nilpotent matching and unification are shown to be JVP-complete. In the presence of associativity and commutativity, the problems still remain NP-complete. But when 0 is also assumed to be the unity for the function f, the problems are solvable in polynomial time. We also show that the problem remains in P even when a homomorphism is added. Second-order matching modulo nilpotence is shown to be undecidable.

Subject area

MECHANISMS unification 


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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Qing Guo
    • 1
  • Paliath Narendran
    • 1
  • D. A. Wolfram
    • 2
  1. 1.Institute of Programming and Logics, Department of Computer ScienceState University of New York at AlbanyAlbanyUSA
  2. 2.Department of Computer ScienceThe Australian National UniversityCanberraAustralia

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