Abstract
We show that there are CNF formulas which can be refuted in resolution in both small space and small width, but for which any small-width proof must have space exceeding by far the linear worst-case upper bound. This significantly strengthens the space-width trade-offs in [E. Ben-Sasson, SIAM J. Comput., 38 (2009), pp. 2511-2525], and provides one more example of trade-offs in the "supercritical" regime above worst case recently identified by [A.A. Razborov, J. ACM, 63 (2016), 16]. We obtain our results by using Razborov's new hardness condensation technique and combining it with the space lower bounds in [E. Ben-Sasson and J. Nordström, Short proofs may be spacious: An optimal separation of space and length in resolution, in Proceedings of the 49th Annual IEEE Symposium on Foundations of Computer Science (FOCS '08), 2008, pp. 709-718].
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | SIAM Journal on Computing |
| Vol/bind | 49 |
| Udgave nummer | 1 |
| Sider (fra-til) | 98-118 |
| ISSN | 0097-5397 |
| DOI | |
| Status | Udgivet - 2020 |
Finansiering
∗Received by the editors December 21, 2016; accepted for publication (in revised form) July 30, 2018; published electronically February 4, 2020. A preliminary version of this work appeared in Proceedings of the 43rd International Colloquium on Automata, Languages and Programming (ICALP′16). https://doi.org/10.1137/16M1109072 Funding: The first author was supported by a fellowship within the Postdoc-Programme of the German Academic Exchange Service (DAAD). The second author was supported by the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007–2013) ERC grant agreement 279611 and by Swedish Research Council grants 621-2010-4797, 621-2012-5645, and 2016-00782.
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