Approximate counting CSP seen from the other side

In this paper we study the complexity of counting Constraint Satisfaction Problems (CSPs) of the form #CSP(C,-), in which the goal is, given a relational structure A from a class C of structures and an arbitrary structure B, to find the number of homomorphisms from A to B. Flum and Grohe showed that...

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Main Authors: Bulatov, A, Zivny, S
Format: Conference item
Published: Schloss Dagstuhl - Leibniz-Zentrum für Informatik 2019
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author Bulatov, A
Zivny, S
author_facet Bulatov, A
Zivny, S
author_sort Bulatov, A
collection OXFORD
description In this paper we study the complexity of counting Constraint Satisfaction Problems (CSPs) of the form #CSP(C,-), in which the goal is, given a relational structure A from a class C of structures and an arbitrary structure B, to find the number of homomorphisms from A to B. Flum and Grohe showed that #CSP(C,-) is solvable in polynomial time if C has bounded treewidth [FOCS'02]. Building on the work of Grohe [JACM'07] on decision CSPs, Dalmau and Jonsson then showed that, if C is a recursively enumerable class of relational structures of bounded arity, then assuming FPT != #W[1], there are no other cases of #CSP(C,-) solvable exactly in polynomial time (or even fixed-parameter time) [TCS'04]. We show that, assuming FPT != W[1] (under randomised parametrised reductions) and for C satisfying certain general conditions, #CSP(C,-) is not solvable even approximately for C of unbounded treewidth; that is, there is no fixed parameter tractable (and thus also not fully polynomial) randomised approximation scheme for #CSP(C,-). In particular, our condition generalises the case when C is closed under taking minors.
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spelling oxford-uuid:a8f43265-d568-416f-8546-175b2ad809222022-03-27T03:05:08ZApproximate counting CSP seen from the other sideConference itemhttp://purl.org/coar/resource_type/c_5794uuid:a8f43265-d568-416f-8546-175b2ad80922Symplectic Elements at OxfordSchloss Dagstuhl - Leibniz-Zentrum für Informatik2019Bulatov, AZivny, SIn this paper we study the complexity of counting Constraint Satisfaction Problems (CSPs) of the form #CSP(C,-), in which the goal is, given a relational structure A from a class C of structures and an arbitrary structure B, to find the number of homomorphisms from A to B. Flum and Grohe showed that #CSP(C,-) is solvable in polynomial time if C has bounded treewidth [FOCS'02]. Building on the work of Grohe [JACM'07] on decision CSPs, Dalmau and Jonsson then showed that, if C is a recursively enumerable class of relational structures of bounded arity, then assuming FPT != #W[1], there are no other cases of #CSP(C,-) solvable exactly in polynomial time (or even fixed-parameter time) [TCS'04]. We show that, assuming FPT != W[1] (under randomised parametrised reductions) and for C satisfying certain general conditions, #CSP(C,-) is not solvable even approximately for C of unbounded treewidth; that is, there is no fixed parameter tractable (and thus also not fully polynomial) randomised approximation scheme for #CSP(C,-). In particular, our condition generalises the case when C is closed under taking minors.
spellingShingle Bulatov, A
Zivny, S
Approximate counting CSP seen from the other side
title Approximate counting CSP seen from the other side
title_full Approximate counting CSP seen from the other side
title_fullStr Approximate counting CSP seen from the other side
title_full_unstemmed Approximate counting CSP seen from the other side
title_short Approximate counting CSP seen from the other side
title_sort approximate counting csp seen from the other side
work_keys_str_mv AT bulatova approximatecountingcspseenfromtheotherside
AT zivnys approximatecountingcspseenfromtheotherside