Uniform hardness versus randomness tradeoffs for Arthur-Merlin games

Dan Gutfreund, Ronen Shaltiel, Amnon Ta-Shma

Research output: Contribution to journalArticlepeer-review


Impagliazzo and Wigderson proved a uniform hardness vs. randomness "gap theorem" for BPP. We show an analogous result for AM: Either Arthur-Merlin protocols are very strong and everything in E = DTIME(2 O(n)) can be proved to a subexponential time verifier, or else Arthur-Merlin protocols are weak and every language in AM has a polynomial time nondeterministic algorithm such that it is infeasible to come up with inputs on which the algorithm fails. We also show that if Arthur-Merlin protocols are not very strong (in the sense explained above) then AM ∩ coAM = NP ∩ coNP. Our technique combines the nonuniform hardness versus randomness tradeoff of Miltersen and Vinodchandran with "instance checking". A key ingredient in our proof is identifying a novel "resilience" property of hardness vs. randomness tradeoffs.

Original languageEnglish
Pages (from-to)85-130
Number of pages46
JournalComputational Complexity
Issue number3-4
StatePublished - 2003
Externally publishedYes

Bibliographical note

Funding Information:
The first author is supported in part by the Leibniz Center, the Israel Foundation of Science, a US-Israel Binational research grant, and an EU Information Technologies grant (IST-FP5). The second author is supported by the Koshland Scholarship.


  • Arthur-Merlin games
  • Derandomization

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Mathematics
  • Computational Theory and Mathematics
  • Computational Mathematics


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