-  Authors: D. van Melkebeek and R. Santhanam.
 -  Reference: SIAM Journal on Computing, 35: 59-90, 2005.
 -  Earlier version:
- R. Santhanam and D. van Melkebeek. 
Holographic proofs and derandomization.
In Proceedings of the 18th Annual IEEE Conference 
on Computational Complexity, pages 269-283, 2003.
 
 
Abstract
We derive a stronger consequence of EXP having 
polynomial-size circuits than was known previously, namely that
for each language L in P, 
and for each efficiently decidable error-correcting code E having 
nontrivial relative distance, there is a simulation of L in 
Merlin-Arthur polylogarithmic time that fools all deterministic 
polynomial-time adversaries for inputs that are codewords of E.
Using the connection between circuit lower bounds and derandomization, 
we obtain uniform assumptions for derandomizing BPP. 
Our results strengthen the space-randomness tradeoffs of Sipser, 
Nisan and Wigderson, and Lu. 
We also consider a more quantitative notion of simulation, where the 
measure of success of the simulation is the fraction of inputs of a 
given length on which the simulation works. Among other results, 
we show that if there is no polynomial time bound t such that P can 
be simulated well by Merlin-Arthur machines operating in time t, 
then for any ε > 0 
there is a simulation of BPP in P that works for all but 
2nε inputs of length n. 
This is a uniform strengthening of a recent result of Goldreich and Wigderson.
Finally, we give an unconditional simulation of multitape Turing machines 
operating in probabilistic time t by Turing machines operating in 
deterministic time o(2t). 
We show similar results for randomized NC1 circuits.
Our proofs are based on a combination of techniques in the theory of 
derandomization with results on holographic proofs.