Title
Time-Space Trade-offs in Resolution: Superpolynomial Lower Bounds for Superlinear Space.
Abstract
We give the first time-space trade-off lower bounds for resolution proofs that apply to superlinear space. In particular, we show that there are formulas of size N that have resolution refutations of size (and space) T(N) = N-Theta(log N) (and like all formulas have another resolution refutation of space N) but for which no resolution refutation can simultaneously have space S(N) = T(N)(o(1)) and size T(N)(O(1)). In other words, any substantial reduction in space results in a super polynomial increase in total size. We also show somewhat stronger time-space trade-off lower bounds for regular resolution, which are also the first to apply to superlinear space. For any function T that is at most weakly exponential, T(N) = 2(o(N1/4)), we give a tautology that has regular resolution proofs of size and space T(N), but no such proofs with space S(N) = T(N)(1-Omega(1)) and size T(N)(O(1)). Thus, any polynomial reduction in space has a superpolynomial cost in size. These tautologies are width 4 disjunctive normal form (DNF) formulas.
Year
DOI
Venue
2016
10.1137/130914085
SIAM JOURNAL ON COMPUTING
Keywords
Field
DocType
proof complexity,resolution,time-space trade-offs,lower bounds
Binary logarithm,Discrete mathematics,Combinatorics,Exponential function,Polynomial,Space trade,Mathematical proof,Omega,Proof complexity,Mathematics
Journal
Volume
Issue
ISSN
45
SP4
0097-5397
Citations 
PageRank 
References 
1
0.37
13
Authors
3
Name
Order
Citations
PageRank
Paul Beame12234176.07
Christopher Beck2271.53
Russell Impagliazzo35444482.13