Log. Methods Comput. Sci.最新文献_第2页

Strategy Complexity of Point Payoff, Mean Payoff and Total Payoff Objectives in Countable MDPs 可计数mdp中点收益、平均收益和总收益目标的策略复杂性

Log. Methods Comput. Sci. Pub Date : 2022-03-10 DOI: 10.46298/lmcs-19(1:16)2023

Richard Mayr, Eric Munday

引用次数: 1

A proof system for graph (non)-isomorphism verification 图(非)同构验证的证明系统

Log. Methods Comput. Sci. Pub Date : 2021-12-28 DOI: 10.46298/lmcs-19(1:9)2023

Milan Bankovi'c, Ivan Drecun, Filip Mari'c

引用次数: 0

A Case Study on Parametric Verification of Failure Detectors 故障检测器参数验证的实例研究

Log. Methods Comput. Sci. Pub Date : 2021-12-16 DOI: 10.46298/lmcs-19(1:17)2023

T. Tran, I. Konnov, Josef Widder

{"title":"A Case Study on Parametric Verification of Failure Detectors","authors":"T. Tran, I. Konnov, Josef Widder","doi":"10.46298/lmcs-19(1:17)2023","DOIUrl":"https://doi.org/10.46298/lmcs-19(1:17)2023","url":null,"abstract":"Partial synchrony is a model of computation in many distributed algorithms\u0000and modern blockchains. These algorithms are typically parameterized in the\u0000number of participants, and their correctness requires the existence of bounds\u0000on message delays and on the relative speed of processes after reaching Global\u0000Stabilization Time. These characteristics make partially synchronous algorithms\u0000parameterized in the number of processes, and parametric in time bounds, which\u0000render automated verification of partially synchronous algorithms challenging.\u0000In this paper, we present a case study on formal verification of both safety\u0000and liveness of the Chandra and Toueg failure detector that is based on partial\u0000synchrony. To this end, we first introduce and formalize the class of symmetric\u0000point-to-point algorithms that contains the failure detector. Second, we show\u0000that these symmetric point-to-point algorithms have a cutoff, and the cutoff\u0000results hold in three models of computation: synchrony, asynchrony, and partial\u0000synchrony. As a result, one can verify them by model checking small instances,\u0000but the verification problem stays parametric in time. Next, we specify the\u0000failure detector and the partial synchrony assumptions in three frameworks:\u0000TLA+, IVy, and counter automata. Importantly, we tune our modeling to use the\u0000strength of each method: (1) We are using counters to encode message buffers\u0000with counter automata, (2) we are using first-order relations to encode message\u0000buffers in IVy, and (3) we are using both approaches in TLA+. By running the\u0000tools for TLA+ and counter automata, we demonstrate safety for fixed time\u0000bounds. By running IVy, we prove safety for arbitrary time bounds. Moreover, we\u0000show how to verify liveness of the failure detector by reducing the\u0000verification problem to safety verification. Thus, both properties are verified\u0000by developing inductive invariants with IVy.","PeriodicalId":314387,"journal":{"name":"Log. Methods Comput. Sci.","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131633858","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

A framework to measure the robustness of programs in the unpredictable environment 在不可预测的环境中衡量程序健壮性的框架

Log. Methods Comput. Sci. Pub Date : 2021-11-30 DOI: 10.46298/lmcs-19(3:2)2023

Valentina Castiglioni, M. Loreti, S. Tini

{"title":"A framework to measure the robustness of programs in the unpredictable environment","authors":"Valentina Castiglioni, M. Loreti, S. Tini","doi":"10.46298/lmcs-19(3:2)2023","DOIUrl":"https://doi.org/10.46298/lmcs-19(3:2)2023","url":null,"abstract":"Due to the diffusion of IoT, modern software systems are often thought to\u0000control and coordinate smart devices in order to manage assets and resources,\u0000and to guarantee efficient behaviours. For this class of systems, which\u0000interact extensively with humans and with their environment, it is thus crucial\u0000to guarantee their correct behaviour in order to avoid unexpected and possibly\u0000dangerous situations. In this paper we will present a framework that allows us\u0000to measure the robustness of systems. This is the ability of a program to\u0000tolerate changes in the environmental conditions and preserving the original\u0000behaviour. In the proposed framework, the interaction of a program with its\u0000environment is represented as a sequence of random variables describing how\u0000both evolve in time. For this reason, the considered measures will be defined\u0000among probability distributions of observed data. The proposed framework will\u0000be then used to define the notions of adaptability and reliability. The former\u0000indicates the ability of a program to absorb perturbation on environmental\u0000conditions after a given amount of time. The latter expresses the ability of a\u0000program to maintain its intended behaviour (up-to some reasonable tolerance)\u0000despite the presence of perturbations in the environment. Moreover, an\u0000algorithm, based on statistical inference, is proposed to evaluate the proposed\u0000metric and the aforementioned properties. We use two case studies to the\u0000describe and evaluate the proposed approach.","PeriodicalId":314387,"journal":{"name":"Log. Methods Comput. Sci.","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125503924","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: 1

Deconfined Global Types for Asynchronous Sessions 异步会话的定义全局类型

Log. Methods Comput. Sci. Pub Date : 2021-11-23 DOI: 10.46298/lmcs-19(1:3)2023

Francesco Dagnino, P. Giannini, M. Dezani-Ciancaglini

引用次数: 7

Modularity and Combination of Associative Commutative Congruence Closure Algorithms enriched with Semantic Properties 丰富语义属性的联想交换同余闭包算法的模块化与组合

Log. Methods Comput. Sci. Pub Date : 2021-11-08 DOI: 10.46298/lmcs-19(1:19)2023

D. Kapur

{"title":"Modularity and Combination of Associative Commutative Congruence Closure Algorithms enriched with Semantic Properties","authors":"D. Kapur","doi":"10.46298/lmcs-19(1:19)2023","DOIUrl":"https://doi.org/10.46298/lmcs-19(1:19)2023","url":null,"abstract":"Algorithms for computing congruence closure of ground equations over\u0000uninterpreted symbols and interpreted symbols satisfying associativity and\u0000commutativity (AC) properties are proposed. The algorithms are based on a\u0000framework for computing a congruence closure by abstracting nonflat terms by\u0000constants as proposed first in Kapur's congruence closure algorithm (RTA97).\u0000The framework is general, flexible, and has been extended also to develop\u0000congruence closure algorithms for the cases when associative-commutative\u0000function symbols can have additional properties including idempotency,\u0000nilpotency, identities, cancellativity and group properties as well as their\u0000various combinations. Algorithms are modular; their correctness and termination\u0000proofs are simple, exploiting modularity. Unlike earlier algorithms, the\u0000proposed algorithms neither rely on complex AC compatible well-founded\u0000orderings on nonvariable terms nor need to use the associative-commutative\u0000unification and extension rules in completion for generating canonical rewrite\u0000systems for congruence closures. They are particularly suited for integrating\u0000into the Satisfiability modulo Theories (SMT) solvers. A new way to view\u0000Groebner basis algorithm for polynomial ideals with integer coefficients as a\u0000combination of the congruence closures over the AC symbol * with the identity 1\u0000and the congruence closure over an Abelian group with + is outlined.","PeriodicalId":314387,"journal":{"name":"Log. Methods Comput. Sci.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134456839","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: 1

Sound approximate and asymptotic probabilistic bisimulations for PCTL PCTL的可靠近似和渐近概率双模拟

Log. Methods Comput. Sci. Pub Date : 2021-11-04 DOI: 10.46298/lmcs-19(1:22)2023

Massimo Bartoletti, Maurizio Murgia, R. Zunino

{"title":"Sound approximate and asymptotic probabilistic bisimulations for PCTL","authors":"Massimo Bartoletti, Maurizio Murgia, R. Zunino","doi":"10.46298/lmcs-19(1:22)2023","DOIUrl":"https://doi.org/10.46298/lmcs-19(1:22)2023","url":null,"abstract":"We tackle the problem of establishing the soundness of approximate\u0000bisimilarity with respect to PCTL and its relaxed semantics. To this purpose,\u0000we consider a notion of bisimilarity inspired by the one introduced by\u0000Desharnais, Laviolette, and Tracol, and parametric with respect to an\u0000approximation error $delta$, and to the depth $n$ of the observation along\u0000traces. Essentially, our soundness theorem establishes that, when a state $q$\u0000satisfies a given formula up-to error $delta$ and steps $n$, and $q$ is\u0000bisimilar to $q'$ up-to error $delta'$ and enough steps, we prove that $q'$\u0000also satisfies the formula up-to a suitable error $delta\"$ and steps $n$. The\u0000new error $delta\"$ is computed from $delta$, $delta'$ and the formula, and\u0000only depends linearly on $n$. We provide a detailed overview of our soundness\u0000proof. We extend our bisimilarity notion to families of states, thus obtaining\u0000an asymptotic equivalence on such families. We then consider an asymptotic\u0000satisfaction relation for PCTL formulae, and prove that asymptotically\u0000equivalent families of states asymptotically satisfy the same formulae.","PeriodicalId":314387,"journal":{"name":"Log. Methods Comput. Sci.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125913508","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

A Strong Call-By-Need Calculus 一个强大的随需调用演算

Log. Methods Comput. Sci. Pub Date : 2021-11-02 DOI: 10.46298/lmcs-19(1:21)2023

Thibaut Balabonski, Antoine Lanco, G. Melquiond

引用次数: 2

On Small Types in Univalent Foundations 一元基础中的小类型

Log. Methods Comput. Sci. Pub Date : 2021-10-31 DOI: 10.46298/lmcs-19(2:8)2023

T. Jong, M. Escard'o

{"title":"On Small Types in Univalent Foundations","authors":"T. Jong, M. Escard'o","doi":"10.46298/lmcs-19(2:8)2023","DOIUrl":"https://doi.org/10.46298/lmcs-19(2:8)2023","url":null,"abstract":"We investigate predicative aspects of constructive univalent foundations. By\u0000predicative and constructive, we respectively mean that we do not assume\u0000Voevodsky's propositional resizing axioms or excluded middle. Our work\u0000complements existing work on predicative mathematics by exploring what cannot\u0000be done predicatively in univalent foundations. Our first main result is that\u0000nontrivial (directed or bounded) complete posets are necessarily large. That\u0000is, if such a nontrivial poset is small, then weak propositional resizing\u0000holds. It is possible to derive full propositional resizing if we strengthen\u0000nontriviality to positivity. The distinction between nontriviality and\u0000positivity is analogous to the distinction between nonemptiness and\u0000inhabitedness. Moreover, we prove that locally small, nontrivial (directed or\u0000bounded) complete posets necessarily lack decidable equality. We prove our\u0000results for a general class of posets, which includes e.g. directed complete\u0000posets, bounded complete posets, sup-lattices and frames. Secondly, the fact\u0000that these nontrivial posets are necessarily large has the important\u0000consequence that Tarski's theorem (and similar results) cannot be applied in\u0000nontrivial instances. Furthermore, we explain that generalizations of Tarski's\u0000theorem that allow for large structures are provably false by showing that the\u0000ordinal of ordinals in a univalent universe has small suprema in the presence\u0000of set quotients. The latter also leads us to investigate the\u0000inter-definability and interaction of type universes of propositional\u0000truncations and set quotients, as well as a set replacement principle. Thirdly,\u0000we clarify, in our predicative setting, the relation between the traditional\u0000definition of sup-lattice that requires suprema for all subsets and our\u0000definition that asks for suprema of all small families.","PeriodicalId":314387,"journal":{"name":"Log. Methods Comput. Sci.","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131744033","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: 3

A modular construction of type theories 类型理论的模块化构造

Log. Methods Comput. Sci. Pub Date : 2021-10-31 DOI: 10.46298/lmcs-19(1:12)2023

F. Blanqui, Gilles Dowek, Émilie Grienenberger, Gabriel Hondet, Franccois Thir'e

引用次数: 3