{"title":"Lower Bounds for Multi-Player Pointer Jumping","authors":"Amit Chakrabarti","doi":"10.1109/CCC.2007.14","DOIUrl":"https://doi.org/10.1109/CCC.2007.14","url":null,"abstract":"We consider the k-layer pointer jumping problem in the one-way multi-party number-on-the-forehead communication model. Sufficiently strong lower bounds for the problem would have major consequences in circuit complexity. We take an information complexity approach to this problem and obtain three lower bounds that improve upon earlier work. For myopic protocols (where players may see only one layer ahead but arbitrarily far behind), we greatly improve a lower bound due to Gronemeier (2006). Our new lower bound is Omega(n/k), where n is the number of vertices per layer. For conservative protocols (where players may see arbitrarily far ahead but not behind, instead seeing only the vertex reached by following the pointers up to their layer), we extend an Omega(n/k2) lower bound due to Damm, Jukna and Sgall (1998) so that it applies for all k. The above two bounds apply even to the Boolean version of pointer jumping. Our third lower bound is for the non-Boolean case and for k les log* n. We obtain an Omega(n log(k-1) n) bound for myopic protocols. Damm et al. had obtained a similar bound for deterministic conservative protocols. All our lower bounds apply directly to randomised protocols.","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127953579","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":"Norms, XOR Lemmas, and Lower Bounds for GF(2) Polynomials and Multiparty Protocols","authors":"Emanuele Viola, A. Wigderson","doi":"10.1109/CCC.2007.15","DOIUrl":"https://doi.org/10.1109/CCC.2007.15","url":null,"abstract":"This paper presents a unified and simple treatment of basic questions concerning two computational models: multiparty communication complexity and GF(2) polynomials. The key is the use of (known) norms on Boolean functions, which capture their approximability in each of these models. The main contributions are new XOR lemmas. We show that if a Boolean function has correlation at most epsi les 1/2 with any of these models, then the correlation of the parity of its values on m independent instances drops exponentially with m. More specifically: For GF(2) polynomials of degree d, the correlation drops to exp (-m/4d). No XOR lemma was known even for d = 2. For c-bit k-party protocols, the correlation drops to 2c ldrepsim/2 k . No XOR lemma was known for k ges 3 parties. Another contribution in this paper is a general derivation of direct product lemmas from XOR lemmas. In particular, assuming that f has correlation at most epsi les 1/2 with any of the above models, we obtain the following bounds on the probability of computing m independent instances of f correctly: For GF(2) polynomials of degree d we again obtain a bound of exp(-m/4d). For c-bit k-party protocols we obtain a bound of 2-Omega(m) in the special case when epsi les exp (-c ldr 2k). In this range of epsi, our bound improves on a direct product lemma for two-parties by Parnafes, Raz, and Wigderson (STOC '97). We also use the norms to give improved (or just simplified) lower bounds in these models. In particular we give a new proof that the Modm function on n bits, for odd m, has correlation at most exp(-n/4d) with degree-d GF(2) polynomials.","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124121421","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 Derandomizing Probabilistic Sublinear-Time Algorithms","authors":"Marius Zimand","doi":"10.1109/CCC.2007.19","DOIUrl":"https://doi.org/10.1109/CCC.2007.19","url":null,"abstract":"There exists a positive constant alpha < 1 such that for any function <i>T</i>(<i>n</i>) les <i>n</i> <sup>alpha</sup> and for any problem <i>L</i> isin BPTIME(<i>T</i>(<i>n</i>)), there exists a deterministic algorithm running in poly(<i>T</i>(<i>n</i>)) time which decides L, except for at most a 2<sup>-Omega</sup> <sup>(T(n)</sup> <sup>log</sup> <sup>T(n))</sup> fraction of inputs of length <i>n</i>.","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127701286","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}
Chris Bourke, Raghunath Tewari, N. V. Vinodchandran
{"title":"Directed Planar Reachability is in Unambiguous Log-Space","authors":"Chris Bourke, Raghunath Tewari, N. V. Vinodchandran","doi":"10.1145/1490270.1490274","DOIUrl":"https://doi.org/10.1145/1490270.1490274","url":null,"abstract":"We show that the st-connectivity problem for directed planar graphs can be decided in unambiguous logarithmic space.","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131181961","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 Parameterized Path and Chordless Path Problems","authors":"Yijia Chen, J. Flum","doi":"10.1109/CCC.2007.21","DOIUrl":"https://doi.org/10.1109/CCC.2007.21","url":null,"abstract":"We study the parameterized complexity of various path (and cycle) problems, the parameter being the length of the path. For example, we show that the problem of the existence of a maximal path of length k in a graph G is fixed-parameter tractable, while its counting version is #W[1]- complete. The corresponding problems for chordless (or induced) paths are W[2]-complete and #W[2]-complete respectively. With the tools developed in this paper we derive the NP-completeness of a related classical problem, thereby solving a problem due to Hedetniemi.","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121255106","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":"Quantum t-designs: t-wise Independence in the Quantum World","authors":"A. Ambainis, J. Emerson","doi":"10.1109/CCC.2007.26","DOIUrl":"https://doi.org/10.1109/CCC.2007.26","url":null,"abstract":"A t-design for quantum states is a finite set of quantum states with the property of simulating the Haar-measure on quantum states w.r.t. any test that uses at most t copies of a state. We give efficient constructions for approximate quantum t-designs for arbitrary t. We then show that an approximate 4-design provides a derandomization of the statedistinction problem considered by Sen (quant-ph/0512085), which is relevant to solving certain instances of the hidden subgroup problem.","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115652936","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":"Quantum versus Classical Proofs and Advice","authors":"S. Aaronson, G. Kuperberg","doi":"10.4086/toc.2007.v003a007","DOIUrl":"https://doi.org/10.4086/toc.2007.v003a007","url":null,"abstract":"This paper studies whether quantum proofs are more powerful than classical proofs, or in complexity terms, whether QMA = QCMA. We prove three results about this question. First, we give a \"quantum oracle separation\" between QMA and QCM A. More concretely, we show that any quantum algorithm needs Omega (radic2n-m+1) queries to find an n-qubit \"marked state\" Psi rang, even if given an m-bit classical description of Psi rang together with a quantum black box that recognizes Psi rang. Second, we give an explicit QCMA protocol that nearly achieves this lower bound. Third, we show that, in the one previously-known case where quantum proofs seemed to provide an exponential advantage, classical proofs are basically just as powerful. In particular, Wa- trous gave a QM IK protocol for verifying non-membership infinite groups. Under plausible group-theoretic assumptions, we give a QCMA protocol for the same problem. Even with no assumptions, our protocol makes only poly-nomially many queries to the group oracle. We end with some conjectures about quantum versus classical oracles, and about the possibility of a classical oracle separation between QMA and QCMA.","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130279093","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":"Ronald V. Book Prize for Best Student Paper Award","authors":"","doi":"10.1109/ccc.2007.29","DOIUrl":"https://doi.org/10.1109/ccc.2007.29","url":null,"abstract":"","PeriodicalId":175854,"journal":{"name":"Twenty-Second Annual IEEE Conference on Computational Complexity (CCC'07)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131605355","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}