Strict sequential P-completeness

  • Klaus Reinhardt
Complexity Theory I
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1200)


In this paper we present a new notion of what it means for a problem in P to be inherently sequential. Informally, a problem L is strictly sequential P-complete if when the best known sequential algorithm for L has polynomial speedup by parallelization, this implies that all problems in P have a polynomial speedup in the parallel setting. The motivation for defining this class of problems is to try and capture the problems in P that axe truly inherently sequential. Our work extends the results of Condon who exhibited problems such that if a polynomial speedup of their best known parallel algorithms could be achieved, then all problems in P would have polynomial speedup. We demonstrate one such natural problem, namely the Multiplex-select Circuit Problem (MCP). MCP has one of the highest degrees of sequentiality of any problem yet defined. On the way to proving MCP is strictly sequential P-complete, we define an interesting model, the register stack machine, that appears to be of independent interest for exploring pure sequentiality.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Klaus Reinhardt
    • 1
  1. 1.Wilhelm-Schickhard Institut für InformatikUniversität TübingenTübingenGermany

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