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Buhrman, Patro, and Speelman [Buhrman et al., 2021] presented a framework of conjectures that together form a quantum analogue of the strong exponential-time hypothesis and its variants. They called it the QSETH framework. In this paper, using a notion of quantum natural proofs (built from natural proofs introduced by Razborov and Rudich), we show how part of the QSETH conjecture that requires properties to be "compression oblivious" can in many cases be replaced by assuming the existence of quantum-secure pseudorandom functions, a standard hardness assumption. Combined with techniques from Fourier analysis of Boolean functions, we show that properties such as parity and majority are compression oblivious for certain circuit class Λ if subexponentially secure quantum pseudorandom functions exist in Λ, answering an open question in [Buhrman et al., 2021].
@InProceedings{chen_et_al:LIPIcs.APPROX/RANDOM.2026.60,
author = {Chen, Yanlin and Chen, Yilei and Kumar, Rajendra and Patro, Subhasree and Speelman, Florian},
title = {{Fine-Grained Complexity via Quantum Natural Proofs}},
booktitle = {Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2026)},
pages = {60:1--60:23},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-449-9},
ISSN = {1868-8969},
year = {2026},
volume = {392},
editor = {Singh, Mohit and Gur, Tom},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.APPROX/RANDOM.2026.60},
URN = {urn:nbn:de:0030-drops-277771},
doi = {10.4230/LIPIcs.APPROX/RANDOM.2026.60},
annote = {Keywords: Fine-grained complexity, Quantum natural proofs, QSETH, Pseudorandom functions}
}