Linear branching programs and directional affine extractors

0559512 - MÚ 2023 RIV DE eng C - Konferenční příspěvek (zahraniční konf.)
Gryaznov, Svyatoslav - Pudlák, Pavel - Talebanfard, Navid
Linear branching programs and directional affine extractors.
37th Computational Complexity Conference (CCC 2022). Dagstuhl: Schloss Dagstuhl, Leibniz-Zentrum für Informatik, 2022 - (Lovett, S.), s. 1-16, č. článku 4. Leibniz International Proceedings in Informatics, 234. ISBN 978-3-95977-241-9. ISSN 1868-8969.
[37th Computational Complexity Conference (CCC 2022). Philadelphia (US), 20.07.2022-23.07.2022]
Grant CEP: GA ČR(CZ) GX19-27871X; GA ČR(CZ) GA19-05497S
Institucionální podpora: RVO:67985840
Klíčová slova: Boolean functions * average-case lower bounds * affine dispersers * affine extractors
Obor OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)
https://doi.org/10.4230/LIPIcs.CCC.2022.4

A natural model of read-once linear branching programs is a branching program where queries are 𝔽₂ linear forms, and along each path, the queries are linearly independent. We consider two restrictions of this model, which we call weakly and strongly read-once, both generalizing standard read-once branching programs and parity decision trees. Our main results are as follows.
- Average-case complexity. We define a pseudo-random class of functions which we call directional affine extractors, and show that these functions are hard on average for the strongly read-once model. We then present an explicit construction of such function with good parameters. This strengthens the result of Cohen and Shinkar (ITCS'16) who gave such average-case hardness for parity decision trees. Directional affine extractors are stronger than the more familiar class of affine extractors. Given the significance of these functions, we expect that our new class of functions might be of independent interest.
- Proof complexity. We also consider the proof system Res[⊕], which is an extension of resolution with linear queries, and define the regular variant of Res[⊕]. A refutation of a CNF in this proof system naturally defines a linear branching program solving the corresponding search problem. If a refutation is regular, we prove that the resulting program is read-once. Conversely, we show that a weakly read-once linear BP solving the search problem can be converted to a regular Res[⊕] refutation with constant blow up, where the regularity condition comes from the definition of weakly read-once BPs, thus obtaining the equivalence between these proof systems.
Trvalý link: https://hdl.handle.net/11104/0332788