Robustness of probabilistic computational complexity classes under definitional perturbations

Computational Error Complexity Classes

The complexity classes Nearly-BPP and Med DisP had been recently proposed as limits of eecient computation Yam1 96, Schi 96]. For both classes, a polynomial time bounded algorithm with bounded probabilistic error has to compute correct outputs for at least 1 ? 1 n !(1) of inputs of length n. We generalize this notion to general error probabilities and arbitrary complexity classes. For proving t...

Probabilistic Algorithms and Complexity Classes

The main theme in this dissertation is a computation on a probabilistic Turing machine (PTM), which is a Turing machine with distinguished states called coin-tossing states. In general, it is assumed that a PTM has a fair coin. This is led by that any xed biased coin can simulate another xed biased coin in a constant expected time. We rst consider the computation which will always terminates in...

Computational Complexity of Probabilistic Disambiguation

Recent models of natural language processing employ statistical reasoning for dealing with the ambiguity of formal grammars. In this approach, statistics, concerning the various linguistic phenomena of interest, are gathered from actual linguistic data and used to estimate the probabilities of the various entities that are generated by a given grammar, e.g., derivations, parse-trees and sentenc...

The Computational Complexity of Probabilistic

We examine the computational complexity of testing and nding small plans in proba-bilistic planning domains with both at and propositional representations. The complexity of plan evaluation and existence varies with the plan type sought; we examine totally ordered plans, acyclic plans, and looping plans, and partially ordered plans under three natural deenitions of plan value. We show that prob...

Probabilistic Computations and Complexity Classes A Survey