On dynamic bit-probe complexity

  • Authors:
  • Mihai Patracu;Corina E. Tarnia

  • Affiliations:
  • MIT, Computer Science and Artificial Intelligence Laboratory, United States;Harvard University, Department of Mathematics, United States

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2007

Quantified Score

Hi-index 5.23

Visualization

Abstract

This work present several advances in the understanding of dynamic data structures in the bit-probe model: *We improve the lower bound record for dynamic language membership problems to @W((lgnlglgn)^2). Surpassing @W(lgn) was listed as the first open problem in a survey by Miltersen. *We prove a bound of @W(lgnlglglgn) for maintaining partial sums in Z/2Z. Previously, the known bounds were @W(lgnlglgn) and O(lgn). *We prove a surprising and tight upper bound of O(lgnlglgn) for the greater-than problem, and several predecessor-type problems. We use this to obtain the same upper bound for dynamic word and prefix problems in group-free monoids. We also obtain new lower bounds for the partial-sums problem in the cell-probe and external-memory models. Our lower bounds are based on a surprising improvement of the classic chronogram technique of Fredman and Saks [Michael L. Fredman, Michael E. Saks, The cell probe complexity of dynamic data structures, in: Proc. 21st ACM Symposium on Theory of Computing STOC, 1989, pp. 345-354], which makes it possible to prove logarithmic lower bounds by this approach. Before the work of M. Pa@?trascu and Demaine [Mihai Pa@?trascu, Erik D. Demaine, Logarithmic lower bounds in the cell-probe model, SIAM Journal on Computing 35 (4) (2006) 932-963. See also SODA'04 and STOC'04], this was the only known technique for dynamic lower bounds, and surpassing @W(lgnlglgn) was a central open problem in cell-probe complexity.