Title
New Unconditional Hardness Results for Dynamic and Online Problems
Abstract
There has been a resurgence of interest in lower bounds whose truth rests on the conjectured hardness of well known computational problems. These conditional lower bounds have become important and popular due to the painfully slow progress on proving strong unconditional lower bounds. Nevertheless, the long term goal is to replace these conditional bounds with unconditional ones. In this paper we make progress in this direction by studying the cell probe complexity of two conjectured to be hard problems of particular importance: matrix-vector multiplication and a version of dynamic set disjointness known as Patrascu's Multiphase Problem. We give improved unconditional lower bounds for these problems as well as introducing new proof techniques of independent interest. These include a technique capable of proving strong threshold lower bounds of the following form: If we insist on having a very fast query time, then the update time has to be slow enough to compute a lookup table with the answer to every possible query. This is the first time a lower bound of this type has been proven.
Year
DOI
Venue
2015
10.1109/FOCS.2015.71
FOCS '15 Proceedings of the 2015 IEEE 56th Annual Symposium on Foundations of Computer Science (FOCS)
Keywords
DocType
Volume
lower bounds,cell-probe model,computational complexity
Journal
abs/1504.01836
ISSN
Citations 
PageRank 
0272-5428
0
0.34
References 
Authors
17
3
Name
Order
Citations
PageRank
Raphaël Clifford126828.57
Allan Grønlund253.45
Kasper Green Larsen335529.32