Computational depth: concept and applications

  • Authors:
  • Luis Antunes;Lance Fortnow;Dieter van Melkebeek;N. V. Vinodchandran

  • Affiliations:
  • DCC-FC & LIACC, University of Porto, Porto, Portugal;Department of Computer Science, University of Chicago, Chicago, IL;Department of Computer Sciences, University of Wisconsin, Madison, WI;Department of Computer Science and Engineering, University of Nebraska, Lincoln, NE

  • Venue:
  • Theoretical Computer Science - Foundations of computation theory (FCT 2003)
  • Year:
  • 2006

Quantified Score

Hi-index 0.00

Visualization

Abstract

We introduce Computational Depth, a measure for the amount of "nonrandom" or "useful" information in a string by considering the difference of various Kolmogorov complexity measures. We investigate three instantiations of Computational Depth: • Basic Computational Depth, a clean notion capturing the spirit of Bennett's Logical Depth. We show that a Turing machine M runs in time polynomial on average over the time-bounded universal distribution if and only if for all inputs x, M uses time exponential in the basic computational depth of x. • Sublinear-time Computational Depth and the resulting concept of Shallow Sets, a generalization of sparse and random sets based on low depth properties of their characteristic sequences. We show that every computable set that is reducible to a shallow set has polynomial-size circuits. • Distinguishing Computational Depth, measuring when strings are easier to recognize than to produce. We show that if a Boolean formula has a nonnegligible fraction of its satisfying assignments with low depth, then we can find a satisfying assignment efficiently.