Computing and Library Services - delivering an inspiring information environment

Random constraint satifaction: flaws and structure

Gent, Ian P., MacIntyre, Ewan, Prosser, Patrick, Smith, Barbara M. and Walsh, Toby (2001) Random constraint satifaction: flaws and structure. Constraints, 6 (4). pp. 345-372. ISSN 1383-7133

Metadata only available from this repository.


A recent theoretical result by Achlioptas et al. shows that many models of random binary constraint satisfaction problems become trivially insoluble as problem size increases. This insolubility is partly due to the presence of flawed variables, variables whose values are all flawed (or unsupported). In this paper, we analyse how seriously existing work has been affected. We survey the literature to identify experimental studies that use models and parameters that may have been affected by flaws. We then estimate theoretically and measure experimentally the size at which flawed variables can be expected to occur. To eliminate flawed values and variables in the models currently used, we introduce a flawless generator which puts a limited amount of structure into the conflict matrix. We prove that such flawless problems are not trivially insoluble for constraint tightnesses up to 1/2. We also prove that the standard models B and C do not suffer from flaws when the constraint tightness is less than the reciprocal of domain size. We consider introducing types of structure into the constraint graph which are rare in random graphs and present experimental results with such structured graphs.

Item Type: Article
Subjects: Q Science > QA Mathematics > QA75 Electronic computers. Computer science
Schools: School of Computing and Engineering
Related URLs:
Depositing User: Cherry Edmunds
Date Deposited: 30 Oct 2008 11:51
Last Modified: 28 Aug 2021 10:42


Downloads per month over past year

Repository Staff Only: item control page

View Item View Item

University of Huddersfield, Queensgate, Huddersfield, HD1 3DH Copyright and Disclaimer All rights reserved ©