Characterizing Direct Product Testing via Coboundary Expansion

STOC ’24, June 24–28, 2024, Vancouver, BC, Canada

Bibliographic Details
Main Authors: Bafna, Mitali, Minzer, Dor
Other Authors: Massachusetts Institute of Technology. Department of Mathematics
Format: Article
Language:English
Published: ACM 2024
Online Access:https://hdl.handle.net/1721.1/155664
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author Bafna, Mitali
Minzer, Dor
author2 Massachusetts Institute of Technology. Department of Mathematics
author_facet Massachusetts Institute of Technology. Department of Mathematics
Bafna, Mitali
Minzer, Dor
author_sort Bafna, Mitali
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spelling mit-1721.1/1556642025-01-08T04:29:28Z Characterizing Direct Product Testing via Coboundary Expansion Bafna, Mitali Minzer, Dor Massachusetts Institute of Technology. Department of Mathematics STOC ’24, June 24–28, 2024, Vancouver, BC, Canada A d-dimensional simplicial complex X is said to support a direct product tester if any locally consistent function defined on its k-faces (where k≪ d) necessarily come from a function over its vertices. More precisely, a direct product tester has a distribution µ over pairs of k-faces (A,A′), and given query access to F: X(k)→{0,1}k it samples (A,A′)∼ µ and checks that F[A]|A∩ A′ = F[A′]|A∩ A′. The tester should have (1) the ”completeness property”, meaning that any assignment F which is a direct product assignment passes the test with probability 1, and (2) the ”soundness property”, meaning that if F passes the test with probability s, then F must be correlated with a direct product function. Dinur and Kaufman showed that a sufficiently good spectral expanding complex X admits a direct product tester in the ”high soundness” regime where s is close to 1. They asked whether there are high dimensional expanders that support direct product tests in the ”low soundness”, when s is close to 0. We give a characterization of high-dimensional expanders that support a direct product tester in the low soundness regime. We show that spectral expansion is insufficient, and the complex must additionally satisfy a variant of coboundary expansion, which we refer to as ”Unique-Games coboundary expanders”. Conversely, we show that this property is also sufficient to get direct product testers. This property can be seen as a high-dimensional generalization of the standard notion of coboundary expansion over non-Abelian groups for 2-dimensional complexes. It asserts that any locally consistent Unique-Games instance obtained using the low-level faces of the complex, must admit a good global solution. 2024-07-11T21:38:05Z 2024-07-11T21:38:05Z 2024-06-10 2024-07-01T07:50:43Z Article http://purl.org/eprint/type/ConferencePaper 979-8-4007-0383-6 https://hdl.handle.net/1721.1/155664 Bafna, Mitali and Minzer, Dor. 2024. "Characterizing Direct Product Testing via Coboundary Expansion." PUBLISHER_CC en 10.1145/3618260.3649714 Creative Commons Attribution https://creativecommons.org/licenses/by/4.0/ The author(s) application/pdf ACM Association for Computing Machinery
spellingShingle Bafna, Mitali
Minzer, Dor
Characterizing Direct Product Testing via Coboundary Expansion
title Characterizing Direct Product Testing via Coboundary Expansion
title_full Characterizing Direct Product Testing via Coboundary Expansion
title_fullStr Characterizing Direct Product Testing via Coboundary Expansion
title_full_unstemmed Characterizing Direct Product Testing via Coboundary Expansion
title_short Characterizing Direct Product Testing via Coboundary Expansion
title_sort characterizing direct product testing via coboundary expansion
url https://hdl.handle.net/1721.1/155664
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