,
Venkatesan Guruswami
,
Aaron Putterman
Creative Commons Attribution 4.0 International license
Given a constraint satisfaction problem (CSP) predicate P ⊆ D^r, the non-redundancy (NRD) of P is the maximum-sized instance on n variables such that for every clause of the instance, there is an assignment which satisfies all clauses but that one. The study of NRD for various CSPs is an active area of research which combines ideas from extremal combinatorics, logic, lattice theory, and other techniques. Complete classifications are known in the cases r = 2 and (|D| = 2, r = 3). In this paper, we give a near-complete classification of the case (|D| = 2, r = 4). Of the 400 distinct non-trivial Boolean predicates of arity 4, we implement an algorithmic procedure which perfectly classifies 397 of them. Of the remaining three, we solve two by reducing to extremal combinatorics problems - leaving the last one as an open question. Along the way, we identify the first Boolean predicate whose non-redundancy asymptotics are non-polynomial.
@InProceedings{brakensiek_et_al:LIPIcs.CP.2026.8,
author = {Brakensiek, Joshua and Guruswami, Venkatesan and Putterman, Aaron},
title = {{Classification of Non-Redundancy of Boolean Predicates of Arity 4}},
booktitle = {32nd International Conference on Principles and Practice of Constraint Programming (CP 2026)},
pages = {8:1--8:24},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-432-1},
ISSN = {1868-8969},
year = {2026},
volume = {379},
editor = {Beldiceanu, Nicolas},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2026.8},
URN = {urn:nbn:de:0030-drops-266412},
doi = {10.4230/LIPIcs.CP.2026.8},
annote = {Keywords: constraint satisfaction problem, redundancy}
}
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