J. Log. Comput.Pub Date : 2021-12-14DOI: 10.1093/logcom/exac067
David Fern'andez-Duque, J. Joosten, F. Pakhomov, Konstnatinos Papafilippou, A. Weiermann
{"title":"Arithmetical and Hyperarithmetical Worm Battles","authors":"David Fern'andez-Duque, J. Joosten, F. Pakhomov, Konstnatinos Papafilippou, A. Weiermann","doi":"10.1093/logcom/exac067","DOIUrl":"https://doi.org/10.1093/logcom/exac067","url":null,"abstract":"\u0000 Japaridze’s provability logic ${operatorname {GLP}}$ has one modality $[n]$ for each natural number and has been used by Beklemishev for a proof theoretic analysis of Peano arithmetic (${operatorname {PA}}$) and related theories. Among other benefits, this analysis yields the so-called Every Worm Dies (${operatorname {EWD}}$) principle, a natural combinatorial statement independent of ${operatorname {PA}}$. Recently, Beklemishev and Pakhomov have studied notions of provability corresponding to transfinite modalities in ${operatorname {GLP}}$. We show that indeed the natural transfinite extension of ${operatorname {GLP}}$ is sound for this interpretation and yields independent combinatorial principles for the second-order theory ${operatorname {ACA}}$ of arithmetical comprehension with full induction. We also provide restricted versions of ${operatorname {EWD}}$ related to the fragments ${operatorname {IvarSigma }}_n$ of PA. In order to prove the latter, we show that standard Hardy functions majorize their variants based on tree ordinals.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128461053","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}
J. Log. Comput.Pub Date : 2021-11-23DOI: 10.1093/logcom/exab090
E. D. Angelis, F. Fioravanti, A. Pettorossi, M. Proietti
{"title":"Satisfiability of Constrained Horn Clauses on Algebraic Data Types: A Transformation-based Approach","authors":"E. D. Angelis, F. Fioravanti, A. Pettorossi, M. Proietti","doi":"10.1093/logcom/exab090","DOIUrl":"https://doi.org/10.1093/logcom/exab090","url":null,"abstract":"We address the problem of checking the satisfiability of Constrained Horn Clauses (CHCs) defined on Algebraic Data Types (ADTs), such as lists and trees. We propose a new technique for transforming CHCs defined on ADTs into CHCs where the arguments of the predicates have only basic types, such as integers and booleans. Thus, our technique avoids, during satisfiability checking, the explicit use of proof rules based on induction over the ADTs. The main extension over previous techniques for ADT removal is a new transformation rule, called differential replacement, which allows us to introduce auxiliary predicates, whose definitions correspond to lemmas that are used when making inductive proofs. We present an algorithm that performs the automatic removal of ADTs by applying the new rule, together with the traditional folding/unfolding rules. We prove that, under suitable hypotheses, the set of the transformed clauses is satisfiable if and only if so is the set of the original clauses. By an experimental evaluation, we show that the use of the new rule significantly improves the effectiveness of ADT removal. We also show that our approach is competitive with respect to tools that extend CHC solvers with the use of inductive rules.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133139882","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}
J. Log. Comput.Pub Date : 2021-11-12DOI: 10.1093/LOGCOM/EXAB066
Sujata Ghosh, Katsuhiko Sano
{"title":"Rely more or less, for better or for worse: Intertwining reliability and preferences","authors":"Sujata Ghosh, Katsuhiko Sano","doi":"10.1093/LOGCOM/EXAB066","DOIUrl":"https://doi.org/10.1093/LOGCOM/EXAB066","url":null,"abstract":"","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133164310","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}
J. Log. Comput.Pub Date : 2021-11-12DOI: 10.1093/logcom/exac059
Noah Kaufmann
{"title":"Classifying all transducer degrees below N3","authors":"Noah Kaufmann","doi":"10.1093/logcom/exac059","DOIUrl":"https://doi.org/10.1093/logcom/exac059","url":null,"abstract":"We answer an open question in the theory of transducer degrees initially posed in [3], on the structure of polynomial transducer degrees, in particular the question of what degrees, if any, lie below the degree of $n^3$. Transducer degrees are the equivalence classes formed by word transformations which can be realized by a finite-state transducer. While there are no general techniques to tell if a word $w_1$ can be transformed into $w_2$ via an FST, the work of Endrullis et al. in [2] provides a test for the class of spiralling functions, which includes all polynomials. We classify fully the degrees of all cubic polynomials which are below $n^3$, and many of the methods can also be used to classify the degrees of polynomials of higher orders.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126739441","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}
J. Log. Comput.Pub Date : 2021-11-03DOI: 10.1093/logcom/exac069
B. Kjos-Hanssen
{"title":"Interpolating between the Jaccard distance and an analogue of the normalized information distance","authors":"B. Kjos-Hanssen","doi":"10.1093/logcom/exac069","DOIUrl":"https://doi.org/10.1093/logcom/exac069","url":null,"abstract":"Jim'enez, Becerra, and Gelbukh (2013) defined a family of\"symmetric Tversky ratio models\"$S_{alpha,beta}$, $0lealphale 1$, $beta>0$. Each function $D_{alpha,beta}=1-S_{alpha,beta}$ is a semimetric on the powerset of a given finite set. We show that $D_{alpha,beta}$ is a metric if and only if $0lealpha le frac12$ and $betage 1/(1-alpha)$. This result is formally verified in the Lean proof assistant. The extreme points of this parametrized space of metrics are $mathcal V_1=D_{1/2,2}$, the Jaccard distance, and $mathcal V_{infty}=D_{0,1}$, an analogue of the normalized information distance of M. Li, Chen, X. Li, Ma, and Vit'anyi (2004). As a second interpolation, in general we also show that $mathcal V_p$ is a metric, $1le pleinfty$, where $$Delta_p(A,B)=(|Bsetminus A|^p+|Asetminus B|^p)^{1/p},$$ $$mathcal V_p(A,B)=frac{Delta_p(A,B)}{|Acap B| + Delta_p(A,B)}.$$","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131691298","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}
J. Log. Comput.Pub Date : 2021-10-01DOI: 10.1093/logcom/exab061
T. Aravanis
{"title":"An ASP-based solver for parametrized-difference revision","authors":"T. Aravanis","doi":"10.1093/logcom/exab061","DOIUrl":"https://doi.org/10.1093/logcom/exab061","url":null,"abstract":"\u0000 In the present article, a solver for the well-behaved concrete revision operators, named parametrized-difference (PD) revision operators, is described. The solver is developed by means of the powerful framework of answer set programming, which constitutes a contemporary modelling tool, oriented towards difficult search problems. Several useful functionalities are supported by the system, namely, dynamic PD revision, query-answering capabilities, integrity-constraints handling and revision under the closed-world assumption. The solver exhibits high performance in a plethora of revision instances, including hard ones of the SATLIB library; the fact that PD revision respects an intuitive relevance-sensitive principle, identified herein, contributes to this high performance. A graphical user interface provides easy interaction with the implemented system, making it a high-end standalone revision-tool for potential artificial intelligence applications.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"276 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127381963","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}
J. Log. Comput.Pub Date : 2021-09-24DOI: 10.1093/logcom/exab057
W. Calvert, D. Cenzer, V. Harizanov
{"title":"Densely computable structures","authors":"W. Calvert, D. Cenzer, V. Harizanov","doi":"10.1093/logcom/exab057","DOIUrl":"https://doi.org/10.1093/logcom/exab057","url":null,"abstract":"\u0000 In recent years, computability theorists have extensively studied generically and coarsely computable sets. This study of approximate computability was originally motivated by asymptotic density problems in combinatorial group theory. We generalize the notions of generic and coarse computability of sets, introduced by Jockusch and Schupp, to arbitrary structures by defining generically and coarsely computable and computably enumerable structures. There are two directions in which these notions could potentially trivialize: either all structures could have a densely computable copy or only those having a computable (or computably enumerable) copy. We show that some particular classes of structures realize each of these extremal conditions, while other classes realize neither of them. To further explore these concepts, we introduce a graded family of elementarity conditions for substructures, in which we require that the dense sets under consideration be ‘strong’ substructures of the original structure. Here, again, for a given class, the notion could trivialize in the same two directions and we show that both are possible. For each class that we investigate, there is some natural number $n$ such that requiring $varSigma _{n}$ elementarity of substructures is enough to trivialize the class of generically or densely computable structures, witnessing the essentially structural character of these notions.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"634 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132927504","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}
J. Log. Comput.Pub Date : 2021-09-20DOI: 10.1093/logcom/exab060
A. Nola, G. Lenzi, Gaetano Vitale
{"title":"Geometry of super-Łukasiewicz logics","authors":"A. Nola, G. Lenzi, Gaetano Vitale","doi":"10.1093/logcom/exab060","DOIUrl":"https://doi.org/10.1093/logcom/exab060","url":null,"abstract":"\u0000 In this work, we provide constructions, characterizations, geometrical dualities and a McNaughton theorem for non-archimedean MV-algebras, which are the semantics of super-Łukasiewicz logics introduced by Komori.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124228806","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}
J. Log. Comput.Pub Date : 2021-09-15DOI: 10.1093/logcom/exac058
A. Dawar, E. Grädel, Moritz Lichter
{"title":"Limitations of the Invertible-Map Equivalences","authors":"A. Dawar, E. Grädel, Moritz Lichter","doi":"10.1093/logcom/exac058","DOIUrl":"https://doi.org/10.1093/logcom/exac058","url":null,"abstract":"\u0000 This note draws conclusions that arise by combining two recent papers, by Anuj Dawar, Erich Grädel and Wied Pakusa, published at ICALP 2019, and by Moritz Lichter, published at LICS 2021. In both papers, the main technical results rely on the combinatorial and algebraic analysis of the invertible-map equivalences ${equiv ^{text {IM}}_{k, Q}}$ on certain variants of Cai–Fürer–Immerman structures (CFI-structures for short). These ${equiv ^{text {IM}}_{k, Q}}$-equivalences, for a natural number $k$ and a set of primes $Q$, refine the well-known Weisfeiler–Leman equivalences used in algorithms for graph isomorphism. The intuition is that two graphs $G{equiv ^{text {IM}}_{k, Q}}H$ cannot be distinguished by iterative refinements of equivalences on $k$-tuples defined via linear operators on vector spaces over fields of characteristic $p in Q$. In the first paper it has been shown, using considerable algebraic machinery, that for a prime $q notin Q$, the ${equiv ^{text {IM}}_{k, Q}}$ equivalences are not strong enough to distinguish between non-isomorphic CFI-structures over the field $mathbb {F}_q$. In the second paper, a similar but not identical construction for CFI-structures over the rings $mathbb {Z}_{2^i}$ has, again by rather involved combinatorial and algebraic arguments, been shown to be indistinguishable with respect to ${equiv ^{text {IM}}_{k, {2}}}$. Together with an earlier work on rank logic, this second result suffices to separate rank logic from polynomial time. We show here that the two approaches can be unified to prove that CFI-structures over the rings $mathbb {Z}_{2^i}$ are in fact indistinguishable with respect to ${equiv ^{text {IM}}_{k, {mathbb {P}}}}$, for the set ${mathbb {P}}$ of all primes. In particular, this implies the following two results. First, there is no fixed $k$ such that the invertible-map equivalence ${equiv ^{text {IM}}_{k, {mathbb {P}}}}$ coincides with isomorphism on all finite graphs. Second, no extension of fixed-point logic by linear-algebraic operators over fields can capture polynomial time.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"6 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116794181","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}
J. Log. Comput.Pub Date : 2021-05-19DOI: 10.1093/LOGCOM/EXAB016
Stephane Demri, Raul Fervari, Alessio Mansutti
{"title":"Internal proof calculi for modal logics with separating conjunction","authors":"Stephane Demri, Raul Fervari, Alessio Mansutti","doi":"10.1093/LOGCOM/EXAB016","DOIUrl":"https://doi.org/10.1093/LOGCOM/EXAB016","url":null,"abstract":"\u0000 Modal separation logics are formalisms that combine modal operators to reason locally, with separating connectives that allow to perform global updates on the models. In this work, we design Hilbert-style proof systems for the modal separation logics $text {MSL}(ast ,langle neq rangle )$ and $text {MSL}(ast ,Diamond )$, where $ast $ is the separating conjunction, $Diamond $ is the standard modal operator and $langle neq rangle $ is the difference modality. The calculi only use the logical languages at hand (no external features such as labels) and can be divided in two main parts. First, normal forms for formulae are designed and the calculi allow to transform every formula into a formula in normal form. Second, another part of the calculi is dedicated to the axiomatization for formulae in normal form, which may still require non-trivial developments but is more manageable.","PeriodicalId":398763,"journal":{"name":"J. Log. Comput.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125500579","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}