Pub Date : 2025-02-15DOI: 10.1016/j.jlamp.2025.101048
Francisco Durán , Carlos Ramírez , Camilo Rocha , Nicolás Pozas
is a domain-specific language designed for specifying asynchronous, event-driven systems. Its computational model is based on actors, i.e., on communicating state machines. This paper presents a formal semantics of using rewriting logic, extending the language's verification capabilities. Implemented in Maude, a rewriting logic language, this semantics enables automated analysis of programs, including reachability analysis, LTL model checking, and statistical model checking. Through illustrative examples, this paper demonstrates how this formalization significantly enhances 's verification capacities in practical scenarios.
{"title":"A rewriting logic semantics for the analysis of P programs","authors":"Francisco Durán , Carlos Ramírez , Camilo Rocha , Nicolás Pozas","doi":"10.1016/j.jlamp.2025.101048","DOIUrl":"10.1016/j.jlamp.2025.101048","url":null,"abstract":"<div><div><span><math><mtext>P</mtext></math></span> is a domain-specific language designed for specifying asynchronous, event-driven systems. Its computational model is based on actors, i.e., on communicating state machines. This paper presents a formal semantics of <span><math><mtext>P</mtext></math></span> using rewriting logic, extending the language's verification capabilities. Implemented in Maude, a rewriting logic language, this semantics enables automated analysis of <span><math><mtext>P</mtext></math></span> programs, including reachability analysis, LTL model checking, and statistical model checking. Through illustrative examples, this paper demonstrates how this formalization significantly enhances <span><math><mtext>P</mtext></math></span>'s verification capacities in practical scenarios.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"144 ","pages":"Article 101048"},"PeriodicalIF":0.7,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jlamp.2024.101033
Misaki Kojima , Naoki Nishida, Yutaka Matsubara
In this paper, as a first step of modeling concurrent programs by logically constrained term rewrite systems (LCTRSs, for short), we show transformations of concurrent programs with semaphore-based exclusive control into LCTRSs. To this end, we show how to encode configurations of concurrent programs with a fixed number of processes. Then, we show how to encode some well-known operations for semaphores by rewrite rules, showing two transformations of concurrent programs with semaphores into LCTRSs. We adopt list-using and list-free approaches to the encoding of waiting queues for semaphores in LCTRSs. While the former straightforwardly uses lists, the latter uses a so-called take-a-number system in order to avoid using any recursive data structures for waiting queues.
{"title":"Transforming concurrent programs with semaphores into logically constrained term rewrite systems","authors":"Misaki Kojima , Naoki Nishida, Yutaka Matsubara","doi":"10.1016/j.jlamp.2024.101033","DOIUrl":"10.1016/j.jlamp.2024.101033","url":null,"abstract":"<div><div>In this paper, as a first step of modeling concurrent programs by logically constrained term rewrite systems (LCTRSs, for short), we show transformations of concurrent programs with semaphore-based exclusive control into LCTRSs. To this end, we show how to encode configurations of concurrent programs with a fixed number of processes. Then, we show how to encode some well-known operations for semaphores by rewrite rules, showing two transformations of concurrent programs with semaphores into LCTRSs. We adopt list-using and list-free approaches to the encoding of waiting queues for semaphores in LCTRSs. While the former straightforwardly uses lists, the latter uses a so-called take-a-number system in order to avoid using any recursive data structures for waiting queues.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"143 ","pages":"Article 101033"},"PeriodicalIF":0.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143170706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jlamp.2024.101034
Víctor García , Santiago Escobar , Kazuhiro Ogata
Digital signatures ensure the authenticity and integrity of digital assets, vital properties for any secure communication. The National Institute of Standards and Technologies launched the Post-Quantum Cryptography project to standardise new algorithms and protocols that are secure against quantum attackers. The post-quantum signature scheme FALCON was one of the finalists. We present a continuation of the first steps towards the formal specification and analysis, in the high-performance language Maude, of signature schemes. We have adapted and improved a previous framework, originally aimed to formally specify and analyse post-quantum key encapsulation mechanisms. As a use case of the new framework, we specify an executable symbolic model of FALCON. On the symbolic model, we verify termination and fairness using LTL formulas with Maude's model checker. Furthermore, authentication, integrity and non-repudiation are analysed through invariant analysis. Integrity and non-repudiation hold, meanwhile, authentication does not hold in our symbolic model.
{"title":"Formalization and analysis of the post-quantum signature scheme FALCON with Maude","authors":"Víctor García , Santiago Escobar , Kazuhiro Ogata","doi":"10.1016/j.jlamp.2024.101034","DOIUrl":"10.1016/j.jlamp.2024.101034","url":null,"abstract":"<div><div>Digital signatures ensure the authenticity and integrity of digital assets, vital properties for any secure communication. The National Institute of Standards and Technologies launched the Post-Quantum Cryptography project to standardise new algorithms and protocols that are secure against quantum attackers. The post-quantum signature scheme FALCON was one of the finalists. We present a continuation of the first steps towards the formal specification and analysis, in the high-performance language Maude, of signature schemes. We have adapted and improved a previous framework, originally aimed to formally specify and analyse post-quantum key encapsulation mechanisms. As a use case of the new framework, we specify an executable symbolic model of FALCON. On the symbolic model, we verify termination and fairness using LTL formulas with Maude's model checker. Furthermore, authentication, integrity and non-repudiation are analysed through invariant analysis. Integrity and non-repudiation hold, meanwhile, authentication does not hold in our symbolic model.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"143 ","pages":"Article 101034"},"PeriodicalIF":0.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143170707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jlamp.2024.101032
Andrei Nacu
Python is a high-level programming language that is strongly, but dynamically typed. In this paper, we propose a type inference framework to compute specifications for Python functions in isolation. To achieve this, we aim to use an abstract-interpretation-based data flow analysis to infer variable types on a subset of Python programs that use built-in types, operators and functions. To evaluate the expressions found in every program point, specifications for the encountered operations and functions are required. We propose a method for extracting these specifications from the Typeshed project, which contains a set of annotations for built-in and popular third-party libraries. These specifications will be used then to extend the proposed type inference to large Python programs.
{"title":"Towards a type-based abstract semantics for Python","authors":"Andrei Nacu","doi":"10.1016/j.jlamp.2024.101032","DOIUrl":"10.1016/j.jlamp.2024.101032","url":null,"abstract":"<div><div>Python is a high-level programming language that is strongly, but dynamically typed. In this paper, we propose a type inference framework to compute specifications for Python functions in isolation. To achieve this, we aim to use an abstract-interpretation-based data flow analysis to infer variable types on a subset of Python programs that use built-in types, operators and functions. To evaluate the expressions found in every program point, specifications for the encountered operations and functions are required. We propose a method for extracting these specifications from the Typeshed project, which contains a set of annotations for built-in and popular third-party libraries. These specifications will be used then to extend the proposed type inference to large Python programs.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"143 ","pages":"Article 101032"},"PeriodicalIF":0.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143170705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multiparty sessions are a foundational model for distributed entities interacting through message passing. Communication is disciplined by global types: well-typed sessions are lock-free and their participants do follow the described protocols. A key issue is the composition of well-typed sessions, that we face via the participants-as-interfaces approach. We study session composition when a client session is connected to compliant server sessions, where compliance is naturally biased towards the client. We prove that a unique session can be constructed by transforming the interface participants of the client and the servers into gateways (that is, forwarders), if the sessions are well-typed and the compliance relation can be proved. The obtained session has a global type that can be derived from the global types of the composing sessions and the proof of compliance among the client and the servers. A novelty of our approach is that in the composition we only ensure Lock-freedom for the client session, disregarding this property for the server sessions, via a partial typing system. This choice strongly simplifies the construction of the gateways. We consider the present study as a further step toward a theory of Open MultiParty Session Types.
{"title":"Open compliance in multiparty sessions with partial typing","authors":"Franco Barbanera , Viviana Bono , Mariangiola Dezani-Ciancaglini","doi":"10.1016/j.jlamp.2025.101046","DOIUrl":"10.1016/j.jlamp.2025.101046","url":null,"abstract":"<div><div>Multiparty sessions are a foundational model for distributed entities interacting through message passing. Communication is disciplined by global types: well-typed sessions are lock-free and their participants do follow the described protocols. A key issue is the composition of well-typed sessions, that we face via the <em>participants-as-interfaces</em> approach. We study session composition when a client session is connected to compliant server sessions, where compliance is naturally biased towards the client. We prove that a unique session can be constructed by transforming the interface participants of the client and the servers into gateways (that is, forwarders), if the sessions are well-typed and the compliance relation can be proved. The obtained session has a global type that can be derived from the global types of the composing sessions and the proof of compliance among the client and the servers. A novelty of our approach is that in the composition we only ensure Lock-freedom for the client session, disregarding this property for the server sessions, via a partial typing system. This choice strongly simplifies the construction of the gateways. We consider the present study as a further step toward a theory of <em>Open</em> MultiParty Session Types.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"144 ","pages":"Article 101046"},"PeriodicalIF":0.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-28DOI: 10.1016/j.jlamp.2025.101045
Naoki Nishida, Misaki Kojima , Ayuka Matsumi
In the last decade, several transformations of an imperative program into a logically constrained term rewrite system (LCTRS, for short) have been investigated and extended. They do not preserve the nesting of statements, generating rewrite rules like transition systems, while function calls are represented by the nesting of function symbols. Structural features of the original program must often be useful in analyzing the transformed LCTRS. To use such features, we have to know how to transform the program into the LCTRS by keeping the correspondence between statements in the program and the introduced auxiliary function symbols in the LCTRS, or by transforming the LCTRS into a control flow graph to, e.g., recover loop information. In this paper, we propose a nesting-preserving transformation of a SIMP program (a C-like integer program) into an LCTRS. The transformation is mostly based on previous work and introduces the nesting of function symbols that correspond to the nesting of statements in the original program. To be more precise, we propose a construction of a tree homomorphism which is used as a post-process of the transformation in previous work, i.e., which is applied to the LCTRS obtained from the program. As a correctness statement for the nesting-preserving transformation, we show that the tree homomorphism is sound and complete for the reduction of the LCTRS.
{"title":"A nesting-preserving transformation of SIMP programs into logically constrained term rewrite systems","authors":"Naoki Nishida, Misaki Kojima , Ayuka Matsumi","doi":"10.1016/j.jlamp.2025.101045","DOIUrl":"10.1016/j.jlamp.2025.101045","url":null,"abstract":"<div><div>In the last decade, several transformations of an imperative program into a logically constrained term rewrite system (LCTRS, for short) have been investigated and extended. They do not preserve the nesting of statements, generating rewrite rules like transition systems, while function calls are represented by the nesting of function symbols. Structural features of the original program must often be useful in analyzing the transformed LCTRS. To use such features, we have to know how to transform the program into the LCTRS by keeping the correspondence between statements in the program and the introduced auxiliary function symbols in the LCTRS, or by transforming the LCTRS into a control flow graph to, e.g., recover loop information. In this paper, we propose a nesting-preserving transformation of a SIMP program (a C-like integer program) into an LCTRS. The transformation is mostly based on previous work and introduces the nesting of function symbols that correspond to the nesting of statements in the original program. To be more precise, we propose a construction of a tree homomorphism which is used as a post-process of the transformation in previous work, i.e., which is applied to the LCTRS obtained from the program. As a correctness statement for the nesting-preserving transformation, we show that the tree homomorphism is sound and complete for the reduction of the LCTRS.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"144 ","pages":"Article 101045"},"PeriodicalIF":0.7,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-16DOI: 10.1016/j.jlamp.2025.101036
José Meseguer
An inductive inference system for proving validity of formulas in the initial algebra of an order-sorted equational theory is presented. It has 21 inference rules. Only 9 of them require user interaction; the remaining 12 can be automated as simplification rules. In this way, a substantial fraction of the proof effort can be automated. Other rules can be automated by tactics. The inference rules are based on advanced equational reasoning techniques, including: equational proof search, equationally defined equality predicates, narrowing, constructor variant unification, variant satisfiability, order-sorted congruence closure, contextual rewriting, ordered rewriting, and recursive path orderings. All these techniques work modulo axioms B, for B any combination of associativity and/or commutativity and/or identity axioms. Most of these inference rules have already been implemented in Maude's NuITP inductive theorem prover.
{"title":"Inductive reasoning with equality predicates, contextual rewriting and variant-based simplification","authors":"José Meseguer","doi":"10.1016/j.jlamp.2025.101036","DOIUrl":"10.1016/j.jlamp.2025.101036","url":null,"abstract":"<div><div>An inductive inference system for proving validity of formulas in the initial algebra <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>E</mi></mrow></msub></math></span> of an order-sorted equational theory <span><math><mi>E</mi></math></span> is presented. It has 21 inference rules. Only 9 of them require user interaction; the remaining 12 can be automated as <em>simplification rules</em>. In this way, a substantial fraction of the proof effort can be automated. Other rules can be automated by tactics. The inference rules are based on advanced equational reasoning techniques, including: equational proof search, equationally defined equality predicates, narrowing, constructor variant unification, variant satisfiability, order-sorted congruence closure, contextual rewriting, ordered rewriting, and recursive path orderings. All these techniques work modulo axioms <em>B</em>, for <em>B</em> any combination of associativity and/or commutativity and/or identity axioms. Most of these inference rules have already been implemented in Maude's <strong>NuITP</strong> inductive theorem prover.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"144 ","pages":"Article 101036"},"PeriodicalIF":0.7,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.jlamp.2024.101022
Ignacio Ballesteros , Clara Benac-Earle , Julio Mariño , Lars-Åke Fredlund , Ángel Herranz
Automatic data generation is a key component of automated software testing. Random generation of test input data can uncover some bugs in software, but its effectiveness decreases when those inputs must satisfy complex properties in order to be meaningful. In this work, we study an evolutionary approach to generate values that can be encoded as algebraic data types plus additional properties. First, the approach is illustrated with the generation of sorted lists. Then, we generalize the technique to arbitrary algebraic data type definitions. Finally, we consider the problem of constrained data types where the data must satisfy some nontrivial property, using the well-known example of red-black trees for our experiments. This example will allow us to introduce the main principles of evolutionary algorithms and how these principles can be applied to obtain valid, nontrivial samples of a given data structure. Our experiments have revealed that this evolutionary approach is able to improve diversity, and increase the size of valid generated values with respect to simple random sampling techniques.
{"title":"Generation of algebraic data type values using evolutionary algorithms","authors":"Ignacio Ballesteros , Clara Benac-Earle , Julio Mariño , Lars-Åke Fredlund , Ángel Herranz","doi":"10.1016/j.jlamp.2024.101022","DOIUrl":"10.1016/j.jlamp.2024.101022","url":null,"abstract":"<div><div>Automatic data generation is a key component of automated software testing. Random generation of test input data can uncover some bugs in software, but its effectiveness decreases when those inputs must satisfy complex properties in order to be meaningful. In this work, we study an evolutionary approach to generate values that can be encoded as algebraic data types plus additional properties. First, the approach is illustrated with the generation of sorted lists. Then, we generalize the technique to arbitrary algebraic data type definitions. Finally, we consider the problem of constrained data types where the data must satisfy some nontrivial property, using the well-known example of red-black trees for our experiments. This example will allow us to introduce the main principles of evolutionary algorithms and how these principles can be applied to obtain valid, nontrivial samples of a given data structure. Our experiments have revealed that this evolutionary approach is able to improve diversity, and increase the size of valid generated values with respect to simple random sampling techniques.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"143 ","pages":"Article 101022"},"PeriodicalIF":0.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.jlamp.2024.101023
Alexandre Madeira , José Nuno Oliveira , José Proença , Renato Neves
{"title":"Logic and Calculi for All on the occasion of Luís Barbosa’s 60th birthday","authors":"Alexandre Madeira , José Nuno Oliveira , José Proença , Renato Neves","doi":"10.1016/j.jlamp.2024.101023","DOIUrl":"10.1016/j.jlamp.2024.101023","url":null,"abstract":"","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"143 ","pages":"Article 101023"},"PeriodicalIF":0.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.jlamp.2024.101021
Wenhui Zhang
Büchi automata have applications in formal verification, e.g., in deciding whether a system satisfies given properties. We provide a definition of Büchi automata based on first order logics for representing infinite state systems, and investigate rules for proving emptiness and non-emptiness of such automata. We then apply these rules to solve the problem of verifying correctness of concurrent transition systems, leading to a relatively complete approach for proving and disproving LTL (Linear Temporal Logic) specifications. This approach overcomes weaknesses of existing work based on well-founded sets in the sense that the relative completeness does not depend on additional specification for ensuring progress of non-stuttering transitions. On the practical aspect, we provide a set of examples with an experimental verification condition generation tool to demonstrate the potential applicability of the approach for the verification of concurrent systems.
{"title":"First order Büchi automata and their application to verification of LTL specifications","authors":"Wenhui Zhang","doi":"10.1016/j.jlamp.2024.101021","DOIUrl":"10.1016/j.jlamp.2024.101021","url":null,"abstract":"<div><div>Büchi automata have applications in formal verification, e.g., in deciding whether a system satisfies given properties. We provide a definition of Büchi automata based on first order logics for representing infinite state systems, and investigate rules for proving emptiness and non-emptiness of such automata. We then apply these rules to solve the problem of verifying correctness of concurrent transition systems, leading to a relatively complete approach for proving and disproving LTL (Linear Temporal Logic) specifications. This approach overcomes weaknesses of existing work based on well-founded sets in the sense that the relative completeness does not depend on additional specification for ensuring progress of non-stuttering transitions. On the practical aspect, we provide a set of examples with an experimental verification condition generation tool to demonstrate the potential applicability of the approach for the verification of concurrent systems.</div></div>","PeriodicalId":48797,"journal":{"name":"Journal of Logical and Algebraic Methods in Programming","volume":"142 ","pages":"Article 101021"},"PeriodicalIF":0.7,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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