{"title":"Quillen Model Categories-Based Notions of Locality of Logics over Finite Structures","authors":"Hendrick Maia","doi":"10.1017/bsl.2021.37","DOIUrl":"https://doi.org/10.1017/bsl.2021.37","url":null,"abstract":"Abstract Locality is a property of logics, whose origins lie in the works of Hanf and Gaifman, having their utility in the context of finite model theory. Such a property is quite useful in proofs of inexpressibility, but it is also useful in establishing normal forms for logical formulas. There are generally two forms of locality: (i’) if two structures \u0000$mathfrak {A}$\u0000 and \u0000$mathfrak {B}$\u0000 realize the same multiset of types of neighborhoods of radius d, then they agree on a given sentence \u0000$Phi $\u0000 . Here d depends only on \u0000$Phi $\u0000 ; (ii’) if the d-neighborhoods of two tuples \u0000$vec {a}_1$\u0000 and \u0000$vec {a}_2$\u0000 in a structure \u0000$mathfrak {A}$\u0000 are isomorphic, then \u0000$mathfrak {A} models Phi (vec {a}_1) Leftrightarrow Phi (vec {a}_2)$\u0000 . Again, d depends on \u0000$Phi $\u0000 , and not on \u0000$mathfrak {A}$\u0000 . Form (i’) originated from Hanf’s works. Form (ii’) came from Gaifman’s theorem. There is no doubt about the usefulness of the notion of locality, which as seen applies to a huge number of situations. However, there is a deficiency in such a notion: all versions of the notion of locality refer to isomorphism of neighborhoods, which is a fairly strong property. For example, where structures simply do not have sufficient isomorphic neighborhoods, versions of the notion of locality obviously cannot be applied. So the question that immediately arises is: would it be possible to weaken such a condition and maintain Hanf/Gaifman-localities? Arenas, Barceló, and Libkin establish a new condition for the notions of locality, weakening the requirement that neighborhoods should be isomorphic, establishing only the condition that they must be indistinguishable in a given logic. That is, instead of requiring \u0000$N_d(vec {a}) cong N_d(vec {b})$\u0000 , you should only require \u0000$N_d(vec {a}) equiv _k N_d(vec {b})$\u0000 , for some \u0000$k geq 0$\u0000 . Using the fact that logical equivalence is often captured by Ehrenfeucht–Fraïssé games, the authors formulate a game-based framework in which logical equivalence-based locality can be defined. Thus, the notion defined by the authors is that of game-based locality. Although quite promising as well as easy to apply, the game-based framework (used to define locality under logical equivalence) has the following problem: if a logic \u0000$mathcal {L}$\u0000 is local (Hanf-, or Gaifman-, or weakly) under isomorphisms, and \u0000$mathcal {L}'$\u0000 is a sub-logic of \u0000$mathcal {L}$\u0000 , then \u0000$mathcal {L}'$\u0000 is local as well. The same, however, is not true for game-based locality: properties of games guaranteeing locality need not be preserved if one passes to weaker games. The question that immediately arises is: is it possible to define the notion of locality under logical equivalence without resorting to game-based frameworks? In this thesis, I present a homotopic variation for locality under logical equivalence, namely a Quillen model category-based framework for locality under k-logical equivalence, for every primitive-positive sentence of quantifier-rank k. Abstract pr","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"39 1","pages":"529 - 530"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87148493","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":"The Buridan-Volpin Derivation System; Properties and Justification","authors":"Sven Storms","doi":"10.1017/bsl.2022.35","DOIUrl":"https://doi.org/10.1017/bsl.2022.35","url":null,"abstract":"Abstract Logic is traditionally considered to be a purely syntactic discipline, at least in principle. However, prof. David Isles has shown that this ideal is not yet met in traditional logic. Semantic residue is present in the assumption that the domain of a variable should be fixed in advance of a derivation, and also in the notion that a numerical notation must refer to a number rather than be considered a mathematical object in and of itself. Based on his work, the central question of this thesis is what kind of logic, if any, results from removing this semantic residue from traditional logic. We differ from traditional logic in two significant ways. The first is that the assumption that a numerical notation must refer to a number is denied. Numerical notations are considered as mathematical objects in their own right, related to each other by means of rewrite rules. The traditional notion of reference is then replaced by the notion of reduction (by means of the rewrite rules) to a normal form. Two numerical notations that reduce to the same normal form would traditionally be considered identical, as they would refer to the same number, and hence they would be interchangeable salva veritate. In the new system, called Buridan-Volpin (BV), the numerical notations themselves are the elements of the domains of variables, and two numerical notations that reduce to the same normal form need not be interchangeable salva veritate, except when they are syntactically identical (i.e., have the same Gödel number). The second is that we do away with the assumption that the domains of variables need to be fixed in advance of a derivation. Instead we focus on what is needed to guarantee preservation of truth in every step of a derivation. These conditions on the domains of the variables, accumulated in the course of a derivation, are combined in a reference grammar. Whereas traditionally a derivation is considered valid when the conclusion follows from the premisses by way of the derivation rules (and possibly axioms), in the BV system a derivation must meet the extra condition that no inconsistency occurs within the reference grammar. For if the reference grammar were to give rise to inconsistency (i.e., it would be impossible to assign domains to all the variables without breaking at least one of the conditions placed on them in the reference grammar), there is no longer a guarantee that truth has been preserved in every step of the derivation, and hence the truth of the conclusion is not guaranteed by the derivation. In Chapter 2 the BV system is introduced in some formal detail. Chapter 3 gives some examples of derivations, notably totality of addition, multiplication and exponentiation, as well as a lemma needed for the proof of Euclid’s Theorem. These examples, taken from prof. Isles’ First-Order Reasoning and Primitive Recursive Natural Number Notations, show that there is a real proof-theoretical difference between traditional logic and the BV syste","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"54 1","pages":"533 - 535"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86963350","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}
Valentine Kabanets, J. Moore, Rehana Patel, S. Shieh, J. Knight, Philipp Hieronymi, Joel Nagloo, Christopher Porter, J. Zapletal
{"title":"2022 NORTH AMERICAN ANNUAL MEETING OF THE ASSOCIATION FOR SYMBOLIC LOGIC Cornell University Ithaca, NY, USA April 7–10, 2022","authors":"Valentine Kabanets, J. Moore, Rehana Patel, S. Shieh, J. Knight, Philipp Hieronymi, Joel Nagloo, Christopher Porter, J. Zapletal","doi":"10.1017/bsl.2022.24","DOIUrl":"https://doi.org/10.1017/bsl.2022.24","url":null,"abstract":"The Connes Embedding Problem is one of the most famous open problems in the theory of von Neumann algebras and can be stated in purely model-theoretic terms: do all II 1 factors have the same universal theory? Here, a II 1 factor is an infinite-dimensional von Neumann algebra that","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"10 1","pages":"536 - 565"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85349999","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":"2022 EUROPEAN SUMMER MEETING OF THE ASSOCIATION FOR SYMBOLIC LOGIC LOGIC COLLOQUIUM 2022 Reykjavík University Reykjavík, Iceland June 27 – July 1, 2022","authors":"","doi":"10.1017/bsl.2022.38","DOIUrl":"https://doi.org/10.1017/bsl.2022.38","url":null,"abstract":"","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"6 1","pages":"566 - 606"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86948408","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}
G. Bezhanishvili, A. Enayat, K. Bimbó, Øystein Linnebo, Paola D’Aquino Anca Muscholl, P. Dybjer, A. Pauly, Albert Atserias, D. Macpherson, M. Atten, Antonio Montalbán, B. V. D. Berg, Christian Retoré, Clinton Conley, Marion Scheepers, B. Hart, Nam Trang, Christian Rosendal
{"title":"BSL volume 28 issue 4 Cover and Front matter","authors":"G. Bezhanishvili, A. Enayat, K. Bimbó, Øystein Linnebo, Paola D’Aquino Anca Muscholl, P. Dybjer, A. Pauly, Albert Atserias, D. Macpherson, M. Atten, Antonio Montalbán, B. V. D. Berg, Christian Retoré, Clinton Conley, Marion Scheepers, B. Hart, Nam Trang, Christian Rosendal","doi":"10.1017/bsl.2022.42","DOIUrl":"https://doi.org/10.1017/bsl.2022.42","url":null,"abstract":"","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"32 1","pages":"f1 - f3"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73878178","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":"Investigations into intuitionistic and other negations","authors":"Satoru Niki","doi":"10.1017/bsl.2022.29","DOIUrl":"https://doi.org/10.1017/bsl.2022.29","url":null,"abstract":"Abstract Intuitionistic logic formalises the foundational ideas of L.E.J. Brouwer’s mathematical programme of intuitionism. It is one of the earliest non-classical logics, and the difference between classical and intuitionistic logic may be interpreted to lie in the law of the excluded middle, which asserts that either a proposition is true or its negation is true. This principle is deemed unacceptable from the constructive point of view, in whose understanding the law means that there is an effective procedure to determine the truth of all propositions. This understanding of the distinction between the two logics supports the view that negation plays a vital role in the formulation of intuitionistic logic. Nonetheless, the formalisation of negation in intuitionistic logic has not been universally accepted, and many alternative accounts of negation have been proposed. Some seek to weaken or strengthen the negation, and others actively supporting negative inferences that are impossible with it. This thesis follows this tradition and investigates various aspects of negation in intuitionistic logic. Firstly, we look at a problem proposed by H. Ishihara, which asks how effectively one can conserve the deducibility of classical theorems into intuitionistic logic, by assuming atomic classes of non-constructive principles. The classes given in this section improve a previous class given by K. Ishii in two respects: (a) instead of a single class for the law of the excluded middle, two classes are given in terms of weaker principles, allowing a finer analysis and (b) the conservation now extends to a subsystem of intuitionistic logic called Glivenko’s logic. This section also discusses the extension of Ishihara’s problem to minimal logic. Secondly, we study the relationship between two frameworks for weak constructive negation, the approach of D. Vakarelov on one hand and the framework of subminimal negation by A. Colacito, D. de Jongh, and A. L. Vargas on the other hand. We capture a version of Vakarelov’s logic with the semantics of the latter framework, and clarify the relationship between the two semantics. This also provides proof-theoretic insights, which results in the formulation of a cut-free sequent calculus for the aforementioned system. Thirdly, we investigate the ways to unify the formalisations of some logics with contra-intuitionistic inferences. The enquiry concerns paraconsistent logics by R. Sylvan and A. B. Gordienko, as well as the logic of co-negation by G. Priest and of empirical negation by M. De and H. Omori. We take Sylvan’s system as basic, and formulate the frame conditions of the defining axioms of the other systems. The conditions are then used to obtain cut-free labelled sequent calculi for the systems. Finally, we consider L. Humberstone’s actuality operator for intuitionistic logic, which can be seen as the dualisation of a contra-intuitionistic negation. A compete axiomatisation of intuitionistic logic with actuality opera","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"1 1","pages":"532 - 532"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89847350","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":"UNDER LOCK AND KEY: A PROOF SYSTEM FOR A MULTIMODAL LOGIC","authors":"G. A. Kavvos, Daniel Gratzer","doi":"10.1017/bsl.2023.14","DOIUrl":"https://doi.org/10.1017/bsl.2023.14","url":null,"abstract":"Abstract We present a proof system for a multimode and multimodal logic, which is based on our previous work on modal Martin-Löf type theory. The specification of modes, modalities, and implications between them is given as a mode theory, i.e., a small 2-category. The logic is extended to a lambda calculus, establishing a Curry–Howard correspondence.","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"6 1","pages":"264 - 293"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82504919","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":"AN ABSTRACT ALGEBRAIC LOGIC STUDY OF DA COSTA’S LOGIC \u0000${mathscr {C}}_1$\u0000 AND SOME OF ITS PARACONSISTENT EXTENSIONS","authors":"Hugo Albuquerque, Carlos Caleiro","doi":"10.1017/bsl.2022.36","DOIUrl":"https://doi.org/10.1017/bsl.2022.36","url":null,"abstract":"Abstract Two famous negative results about da Costa’s paraconsistent logic \u0000${mathscr {C}}_1$\u0000 (the failure of the Lindenbaum–Tarski process [44] and its non-algebraizability [39]) have placed \u0000${mathscr {C}}_1$\u0000 seemingly as an exception to the scope of Abstract Algebraic Logic (AAL). In this paper we undertake a thorough AAL study of da Costa’s logic \u0000${mathscr {C}}_1$\u0000 . On the one hand, we strengthen the negative results about \u0000${mathscr {C}}_1$\u0000 by proving that it does not admit any algebraic semantics whatsoever in the sense of Blok and Pigozzi (a weaker notion than algebraizability also introduced in the monograph [6]). On the other hand, \u0000${mathscr {C}}_1$\u0000 is a protoalgebraic logic satisfying a Deduction-Detachment Theorem (DDT). We then extend our AAL study to some paraconsistent axiomatic extensions of \u0000${mathscr {C}}_1$\u0000 covered in the literature. We prove that for extensions \u0000${mathcal {S}}$\u0000 such as \u0000${mathcal {C}ilo}$\u0000 [26], every algebra in \u0000${mathsf {Alg}}^*({mathcal {S}})$\u0000 contains a Boolean subalgebra, and for extensions \u0000${mathcal {S}}$\u0000 such as , , or [16, 53], every subdirectly irreducible algebra in \u0000${mathsf {Alg}}^*({mathcal {S}})$\u0000 has cardinality at most 3. We also characterize the quasivariety \u0000${mathsf {Alg}}^*({mathcal {S}})$\u0000 and the intrinsic variety \u0000$mathbb {V}({mathcal {S}})$\u0000 , with , , and .","PeriodicalId":22265,"journal":{"name":"The Bulletin of Symbolic Logic","volume":"12 1","pages":"477 - 528"},"PeriodicalIF":0.0,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76442278","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}