Italian Conference on Theoretical Computer Science最新文献_第3页

Clairvoyance and Laziness for on Line Travelling Agents 在线旅行社的洞察力和懒惰

Italian Conference on Theoretical Computer Science Pub Date : 2007-09-01 DOI: 10.1142/9789812770998_0001

G. Ausiello

引用次数: 0

The Measure Hypothesis and Efficiency of Polynomial Time Approximation Schemes 多项式时间逼近方案的测度假设与效率

Italian Conference on Theoretical Computer Science Pub Date : 2007-09-01 DOI: 10.1142/9789812770998_0017

Mathias Hauptmann

{"title":"The Measure Hypothesis and Efficiency of Polynomial Time Approximation Schemes","authors":"Mathias Hauptmann","doi":"10.1142/9789812770998_0017","DOIUrl":"https://doi.org/10.1142/9789812770998_0017","url":null,"abstract":"A polyomial time approximation scheme for an optimization problem X is an algorithm A such that for each instance x of X and each ǫ > 0, A computes a (1 + ǫ)-approximate solution to instance x of X in time is O(|x|f(1/ǫ)) for some function f . If the running time of A is instead bounded by g(1/ǫ) · |x|O(1) for some function g, A is called an efficient polynomial time approximation scheme. PTAS denotes the class of all NP optimization problems for which a polytime approximation scheme exists, and EPTAS is the class of all such problems for which an efficient polytime approximation scheme exists. It is an open question whether P 6= NP implies the strictness of the inclusion EPTAS ⊆ PTAS. Bazgan [2] and independently Cesati and Trevisan [5] gave a separation under the stronger assumption FPT 6= W [P ]. In this paper we prove EPTAS ( PTAS under some different assumption, namely existence of NP search problems ΠR with a superpolynomial lower bound for the deterministic time complexity. This assumption is weaker than the NP Machine Hypothesis [15] and hence is implied by the Measure Hypothesis μp(NP ) 6= 0. Furthermore, using a sophisticated combinatorial counting argument we construct a recursive oracle under which our assumption holds but that of Cesati and Trevisan does not hold, implying that using relativizing proof techniques one cannot show that our assumption implies FPT 6= W [P ].","PeriodicalId":212849,"journal":{"name":"Italian Conference on Theoretical Computer Science","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121313704","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}

引用次数: 0

Symmetries in Foundations 基础中的对称性

Italian Conference on Theoretical Computer Science Pub Date : 2007-09-01 DOI: 10.1142/9789812770998_0005

G. Longo

引用次数: 0

Weak Markovian Bisimilarity: Abstracting from Prioritized/Weighted Internal Immediate Actions 弱马尔可夫双相似性:从优先/加权的内部即时动作中提取

Italian Conference on Theoretical Computer Science Pub Date : 2007-09-01 DOI: 10.1142/9789812770998_0008

M. Bernardo, A. Aldini

引用次数: 12

On the Approximability of Dense Steiner Tree Problems 稠密Steiner树问题的逼近性

Italian Conference on Theoretical Computer Science Pub Date : 2007-09-01 DOI: 10.1142/9789812770998_0006

Mathias Hauptmann

引用次数: 2

On Defining Proofs of Knowledge in the Bare Public Key Model 关于裸公钥模型中知识证明的定义

Italian Conference on Theoretical Computer Science Pub Date : 2007-09-01 DOI: 10.1142/9789812770998_0020

G. D. Crescenzo, Ivan Visconti

{"title":"On Defining Proofs of Knowledge in the Bare Public Key Model","authors":"G. D. Crescenzo, Ivan Visconti","doi":"10.1142/9789812770998_0020","DOIUrl":"https://doi.org/10.1142/9789812770998_0020","url":null,"abstract":"One contribution provided by the groundbreaking concept of interactive proofs is the notion of proofs of knowledge, where a prover can convince a verifier that she knows a secret related to a public statement. This notion was formalized in the conventional complexity-theoretic model of interactive protocols and showed to be very useful for cryptographic applications, such as entity authentication schemes. Motivated by these applicability considerations, in this paper, we consider proofs of knowledge in a cryptographic model, called the bare public-key model (BPK model in short), where round-efficient interactive proofs with strong variants of security against provers (i.e., soundness) and security against verifiers (i.e., zero-knowledge) have been presented. We formally define notions of proofs of knowledge in the BPK model, and show that there are 4 distinct such notions for each of the previously studied four known notions of soundness. Finally, under the existence of any homomorphic one-way function family, (a generalization of) a 4-round argument system for all NP languages from the literature is a proof of knowledge that is secure against concurrent attacks from provers or verifiers.","PeriodicalId":212849,"journal":{"name":"Italian Conference on Theoretical Computer Science","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126557166","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}

引用次数: 10

Proving the Range Property for Lambda Theories and Models 证明Lambda理论和模型的值域性质

Italian Conference on Theoretical Computer Science Pub Date : 2007-09-01 DOI: 10.1142/9789812770998_0002

H. Barendregt

引用次数: 0

Two Variables Are Not Enough 两个变量是不够的

Italian Conference on Theoretical Computer Science Pub Date : 2005-10-12 DOI: 10.1007/11560586_32

R. Statman

引用次数: 1

Mobile Agents Computing: Security Issues and Algorithmic Solutions 移动代理计算:安全问题和算法解决方案

Italian Conference on Theoretical Computer Science Pub Date : 2005-10-12 DOI: 10.1007/11560586_3

N. Santoro

引用次数: 0

On the Computational Complexity of the L(2, 1)-Labeling Problem for Regular Graphs 正则图的L(2,1)-标记问题的计算复杂度

Italian Conference on Theoretical Computer Science Pub Date : 2005-10-12 DOI: 10.1007/11560586_19

J. Fiala, Jan Kratochvíl

引用次数: 10