{"title":"Dependency schemes in CDCL-based QBF solving: a proof-theoretic study","authors":"Abhimanyu Choudhury, M. Mahajan","doi":"10.4230/LIPIcs.FSTTCS.2023.38","DOIUrl":"https://doi.org/10.4230/LIPIcs.FSTTCS.2023.38","url":null,"abstract":"In Quantified Boolean Formulas QBFs, dependency schemes help to detect spurious or superfluous dependencies that are implied by the variable ordering in the quantifier prefix but are not essential for constructing countermodels. This detection can provably shorten refutations in specific proof systems, and is expected to speed up runs of QBF solvers. The proof system $$texttt{QCDCL}$$\u0000 QCDCL\u0000 recently defined by Beyersdorff and Boehm (LMCS 2023) abstracts the reasoning employed by QBF solvers based on conflict-driven clause-learning (CDCL) techniques. We show how to incorporate the use of dependency schemes into this proof system, either in a preprocessing phase, or in the propagations and clause learning, or both. We then show that when the reflexive resolution path dependency scheme $$texttt{D}^{texttt{rrs}}$$\u0000 \u0000 D\u0000 rrs\u0000 \u0000 is used, a mixed picture emerges: the proof systems that add $$texttt{D}^{texttt{rrs}}$$\u0000 \u0000 D\u0000 rrs\u0000 \u0000 to $$texttt{QCDCL}$$\u0000 QCDCL\u0000 in these three ways are not only incomparable with each other, but are also incomparable with the basic $$texttt{QCDCL}$$\u0000 QCDCL\u0000 proof system that does not use $$texttt{D}^{texttt{rrs}}$$\u0000 \u0000 D\u0000 rrs\u0000 \u0000 at all, as well as with several other resolution-based QBF proof systems. A notable fact is that all our separations are achieved through QBFs with bounded quantifier alternation.","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"69 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141808304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fractional Linear Matroid Matching is in quasi-NC","authors":"Rohit Gurjar, Taihei Oki, Roshan Raj","doi":"10.48550/arXiv.2402.18276","DOIUrl":"https://doi.org/10.48550/arXiv.2402.18276","url":null,"abstract":"The matching and linear matroid intersection problems are solvable in quasi-NC, meaning that there exist deterministic algorithms that run in polylogarithmic time and use quasi-polynomially many parallel processors. However, such a parallel algorithm is unknown for linear matroid matching, which generalizes both of these problems. In this work, we propose a quasi-NC algorithm for fractional linear matroid matching, which is a relaxation of linear matroid matching and commonly generalizes fractional matching and linear matroid intersection. Our algorithm builds upon the connection of fractional matroid matching to non-commutative Edmonds' problem recently revealed by Oki and Soma~(2023). As a corollary, we also solve black-box non-commutative Edmonds' problem with rank-two skew-symmetric coefficients.","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"28 17","pages":"TR24-044"},"PeriodicalIF":0.0,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140419403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Aaronson-Ambainis Conjecture Is True For Random Restrictions","authors":"Sreejata Kishor Bhattacharya","doi":"10.48550/arXiv.2402.13952","DOIUrl":"https://doi.org/10.48550/arXiv.2402.13952","url":null,"abstract":"In an attempt to show that the acceptance probability of a quantum query algorithm making $q$ queries can be well-approximated almost everywhere by a classical decision tree of depth $leq text{poly}(q)$, Aaronson and Ambainis proposed the following conjecture: let $f: { pm 1}^n rightarrow [0,1]$ be a degree $d$ polynomial with variance $geq epsilon$. Then, there exists a coordinate of $f$ with influence $geq text{poly} (epsilon, 1/d)$. We show that for any polynomial $f: { pm 1}^n rightarrow [0,1]$ of degree $d$ $(d geq 2)$ and variance $text{Var}[f] geq 1/d$, if $rho$ denotes a random restriction with survival probability $dfrac{log(d)}{C_1 d}$, $$ text{Pr} left[f_{rho} text{ has a coordinate with influence} geq dfrac{text{Var}[f]^2 }{d^{C_2}} right] geq dfrac{text{Var}[f] log(d)}{50C_1 d}$$ where $C_1, C_2>0$ are universal constants. Thus, Aaronson-Ambainis conjecture is true for a non-negligible fraction of random restrictions of the given polynomial assuming its variance is not too low.","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"229 3","pages":"TR24-035"},"PeriodicalIF":0.0,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140443729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimal Pseudorandom Generators for Low-Degree Polynomials Over Moderately Large Fields","authors":"Ashish Dwivedi, Zeyu Guo, Ben lee Volk","doi":"10.48550/arXiv.2402.11915","DOIUrl":"https://doi.org/10.48550/arXiv.2402.11915","url":null,"abstract":"We construct explicit pseudorandom generators that fool $n$-variate polynomials of degree at most $d$ over a finite field $mathbb{F}_q$. The seed length of our generators is $O(d log n + log q)$, over fields of size exponential in $d$ and characteristic at least $d(d-1)+1$. Previous constructions such as Bogdanov's (STOC 2005) and Derksen and Viola's (FOCS 2022) had either suboptimal seed length or required the field size to depend on $n$. Our approach follows Bogdanov's paradigm while incorporating techniques from Lecerf's factorization algorithm (J. Symb. Comput. 2007) and insights from the construction of Derksen and Viola regarding the role of indecomposability of polynomials.","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"28 24","pages":"TR24-028"},"PeriodicalIF":0.0,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140450027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Siddhartha Jain, Jiawei Li, Robert Robere, Zhiyang Xun
{"title":"On Pigeonhole Principles and Ramsey in TFNP","authors":"Siddhartha Jain, Jiawei Li, Robert Robere, Zhiyang Xun","doi":"10.48550/arXiv.2401.12604","DOIUrl":"https://doi.org/10.48550/arXiv.2401.12604","url":null,"abstract":"The generalized pigeonhole principle says that if tN + 1 pigeons are put into N holes then there must be a hole containing at least t + 1 pigeons. Let t-PPP denote the class of all total NP-search problems reducible to finding such a t-collision of pigeons. We introduce a new hierarchy of classes defined by the problems t-PPP. In addition to being natural problems in TFNP, we show that classes in and above the hierarchy are related to the notion of multi-collision resistance in cryptography, and contain the problem underlying the breakthrough average-case quantum advantage result shown by Yamakawa&Zhandry (FOCS 2022). Finally, we give lower bound techniques for the black-box versions of t-PPP for any t. In particular, we prove that RAMSEY is not in t-PPP, for any t that is sub-polynomial in log (N), in the black-box setting. Goldberg and Papadimitriou conjectured that RAMSEY reduces to 2-PPP, we thus refute it and more in the black-box setting. We also provide an ensemble of black-box separations which resolve the relative complexity of the t-PPP classes with other well-known TFNP classes.","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"27 1","pages":"TR24-017"},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140498550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Unambiguous parity-query complexity","authors":"Dmytro Gavinsky","doi":"10.48550/arXiv.2401.11274","DOIUrl":"https://doi.org/10.48550/arXiv.2401.11274","url":null,"abstract":"We give a lower bound of $Omega(sqrt n)$ on the unambiguous randomised parity-query complexity of the approximate majority problem -- that is, on the lowest randomised parity-query complexity of any function over ${0,1}^n$ whose value is\"0\"if the Hamming weight of the input is at most n/3, is\"1\"if the weight is at least 2n/3, and may be arbitrary otherwise.","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"46 3","pages":"TR24-009"},"PeriodicalIF":0.0,"publicationDate":"2024-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140502302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Upper Bounds on Communication in terms of Approximate Rank","authors":"A. Gál, Ridwan Syed","doi":"10.1007/978-3-030-79416-3_7","DOIUrl":"https://doi.org/10.1007/978-3-030-79416-3_7","url":null,"abstract":"","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"19 1","pages":"116-130"},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83776531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On Hardness Assumptions Needed for \"Extreme High-End\" PRGs and Fast Derandomization","authors":"Ronen Shaltiel, Emanuele Viola","doi":"10.4230/LIPIcs.ITCS.2022.116","DOIUrl":"https://doi.org/10.4230/LIPIcs.ITCS.2022.116","url":null,"abstract":"The hardness vs.~randomness paradigm aims to explicitly construct pseudorandom generators $G:{0,1}^r rightarrow {0,1}^m$ that fool circuits of size $m$, assuming the existence of explicit hard functions. A ``high-end PRG'' with seed length $r=O(log m)$ (implying BPP=P) was achieved in a seminal work of Impagliazzo and Wigderson (STOC 1997), assuming the high-end hardness assumption: there exist constants $0<beta<1<B$, and functions computable in time $2^{B cdot n}$ that cannot be computed by circuits of size $2^{beta cdot n}$. Recently, motivated by fast derandomization of randomized algorithms, Doron et al.~(FOCS 2020) and Chen and Tell (STOC 2021), construct ``extreme high-end PRGs'' with seed length $r=(1+o(1))cdot log m$, under qualitatively stronger assumptions. We study whether extreme high-end PRGs can be constructed from the following scaled version of the assumption which we call ``the extreme high-end hardness assumption'', and in which $beta=1-o(1)$ and $B=1+o(1)$. We give a partial negative answer, showing that certain approaches cannot yield a black-box proof. (A longer abstract with more details appears in the PDF file)","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"126 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73599176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On correlation bounds against polynomials","authors":"P. Ivanov, Liam Pavlovic, Emanuele Viola","doi":"10.4230/LIPIcs.CCC.2023.3","DOIUrl":"https://doi.org/10.4230/LIPIcs.CCC.2023.3","url":null,"abstract":"We study the fundamental challenge of exhibiting explicit functions that have small correlation with low-degree polynomials over $mathbb{F}_{2}$. Our main contributions include: 1. In STOC 2020, CHHLZ introduced a new technique to prove correlation bounds. Using their technique they established new correlation bounds for low-degree polynomials. They conjectured that their technique generalizes to higher degree polynomials as well. We give a counterexample to their conjecture, in fact ruling out weaker parameters and showing what they prove is essentially the best possible. 2. We propose a new approach for proving correlation bounds with the central\"mod functions\", consisting of two steps: (I) the polynomials that maximize correlation are symmetric and (II) symmetric polynomials have small correlation. Contrary to related results in the literature, we conjecture that (I) is true. We argue this approach is not affected by existing\"barrier results\". 3. We prove our conjecture for quadratic polynomials. Specifically, we determine the maximum possible correlation between quadratic polynomials modulo 2 and the functions $(x_{1},dots,x_{n})to z^{sum x_{i}}$ for any $z$ on the complex unit circle; and show that it is achieved by symmetric polynomials. To obtain our results we develop a new proof technique: we express correlation in terms of directional derivatives and analyze it by slowly restricting the direction. 4. We make partial progress on the conjecture for cubic polynomials, in particular proving tight correlation bounds for cubic polynomials whose degree-3 part is symmetric.","PeriodicalId":11639,"journal":{"name":"Electron. Colloquium Comput. Complex.","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77508003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}