6533b851fe1ef96bd12a97e8

RESEARCH PRODUCT

Finite state verifiers with constant randomness

A. C. Cem SayAbuzer Yakaryilmaz

subject

FOS: Computer and information sciencesDiscrete mathematicsClass (set theory)Computer Science - Logic in Computer ScienceFinite-state machineGeneral Computer ScienceComputational Complexity (cs.CC)Binary logarithmLogic in Computer Science (cs.LO)Theoretical Computer ScienceComputer Science - Computational ComplexityBounded functionVerifiable secret sharingConstant (mathematics)Time complexityRandomnessMathematics

description

We give a new characterization of $\mathsf{NL}$ as the class of languages whose members have certificates that can be verified with small error in polynomial time by finite state machines that use a constant number of random bits, as opposed to its conventional description in terms of deterministic logarithmic-space verifiers. It turns out that allowing two-way interaction with the prover does not change the class of verifiable languages, and that no polynomially bounded amount of randomness is useful for constant-memory computers when used as language recognizers, or public-coin verifiers. A corollary of our main result is that the class of outcome problems corresponding to O(log n)-space bounded games of incomplete information where the universal player is allowed a constant number of moves equals NL.

10.2168/lmcs-10(3:6)2014http://arxiv.org/abs/1102.2719