{"title":"On Building Constructive Formal Theories of Computation Noting the Roles of Turing, Church, and Brouwer","authors":"R. Constable","doi":"10.1109/LICS.2012.9","DOIUrl":"https://doi.org/10.1109/LICS.2012.9","url":null,"abstract":"In this article I will examine a few key concepts and design decisions that account for the high value of implemented constructive type theories in computer science. I'll stress the historical fact that these theories, and the proof assistants that animate them, were born from a strong partnership linking computer science, logic, and mathematics. I will recall how modern type theory researchers built on deep insights from the earliest pioneers: Turing - the first computer scientist, Church - the patriarch of logic in computer science, and Brouwer - a singular pioneer of intuitionism and constructive mathematics. They created solid intellectual ground on which to build a formal implemented constructive theory of computation whose influence will be felt well beyond computing and information science alone. All generations of constructive type theory researchers since this beginning have had leaders from all three disciplines. Much of the seminal modern work creating these type theories and their proof assistants was presented in LICS proceedings, and LICS could be a natural home for future work in this flourishing area which is the epitome of logic in computer science.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"384 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122709952","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":"Capsules and Separation","authors":"Jean-Baptiste Jeannin, D. Kozen","doi":"10.1109/LICS.2012.52","DOIUrl":"https://doi.org/10.1109/LICS.2012.52","url":null,"abstract":"We study a formulation of separation logic using capsules, a representation of the state of a computation in higher-order programming languages with mutable variables. We prove soundness of the frame rule in this context and investigate alternative formulations with weaker side conditions.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123972396","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":"Privacy, Anonymity, and Accountability in Ad-Supported Services","authors":"J. Feigenbaum","doi":"10.1109/LICS.2012.10","DOIUrl":"https://doi.org/10.1109/LICS.2012.10","url":null,"abstract":"In this talk, I will address three aspects of user privacy in advertiser-supported, online services. First, I present the design of a novel browser plug-in that enables anonymous search. Next, I consider economic aspects of user privacy from the point of view of the operator of an advertiser-supported website. Finally, I present recent work on \"accountability\" in online activity, where the goal is to hold website operators responsible for appropriate handling of users' sensitive information rather than to prevent users from ever providing information that might be misused.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128442432","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":"A Computational Interpretation of Parametricity","authors":"Jean-Philippe Bernardy, Guilhem Moulin","doi":"10.1109/LICS.2012.25","DOIUrl":"https://doi.org/10.1109/LICS.2012.25","url":null,"abstract":"Reynolds' abstraction theorem has recently been extended to lambda-calculi with dependent types. In this paper, we show how this theorem can be internalized. More precisely, we describe an extension of the Pure Type Systems with a special parametricity rule (with computational content), and prove fundamental properties such as Church-Rosser's and strong normalization. All instances of the abstraction theorem can be both expressed and proved in the calculus itself. Moreover, one can apply parametricity to the parametricity rule: parametricity is itself parametric.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131146985","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":"Extending Type Theory with Forcing","authors":"Guilhem Jaber, Nicolas Tabareau, Matthieu Sozeau","doi":"10.1109/LICS.2012.49","DOIUrl":"https://doi.org/10.1109/LICS.2012.49","url":null,"abstract":"This paper presents an intuitionistic forcing translation for the Calculus of Constructions (CoC), a translation that corresponds to an internalization of the presheaf construction in CoC. Depending on the chosen set of forcing conditions, the resulting type theory can be extended with extra logical principles. The translation is proven correct---in the sense that it preserves type checking---and has been implemented in Coq. As a case study, we show how the forcing translation on integers (which corresponds to the internalization of the topos of trees) allows us to define general inductive types in Coq, without the strict positivity condition. Using such general inductive types, we can construct a shallow embedding of the pure lambda-calculus in Coq, without defining an axiom on the existence of an universal domain. We also build another forcing layer where we prove the negation of the continuum hypothesis.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129952478","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 Complete Proof Theory of Hybrid Systems","authors":"André Platzer","doi":"10.1109/LICS.2012.64","DOIUrl":"https://doi.org/10.1109/LICS.2012.64","url":null,"abstract":"Hybrid systems are a fusion of continuous dynamical systems and discrete dynamical systems. They freely combine dynamical features from both worlds. For that reason, it has often been claimed that hybrid systems are more challenging than continuous dynamical systems and than discrete systems. We now show that, proof-theoretically, this is not the case. We present a complete proof-theoretical alignment that interreduces the discrete dynamics and the continuous dynamics of hybrid systems. We give a sound and complete axiomatization of hybrid systems relative to continuous dynamical systems and a sound and complete axiomatization of hybrid systems relative to discrete dynamical systems. Thanks to our axiomatization, proving properties of hybrid systems is exactly the same as proving properties of continuous dynamical systems and again, exactly the same as proving properties of discrete dynamical systems. This fundamental cornerstone sheds light on the nature of hybridness and enables flexible and provably perfect combinations of discrete reasoning with continuous reasoning that lift to all aspects of hybrid systems and their fragments.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121150399","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":"First-Order and Monadic Second-Order Model-Checking on Ordered Structures","authors":"Viktor Engelmann, S. Kreutzer, S. Siebertz","doi":"10.1109/LICS.2012.38","DOIUrl":"https://doi.org/10.1109/LICS.2012.38","url":null,"abstract":"Model-checking for first- and monadic second-order logic in the context of graphs has received considerable attention in the literature. It is well-known that the problem of verifying whether a formula of these logics is true in a graph is computationally intractable but it does become tractable on interesting classes of graphs such as classes of bounded tree-width. In this paper we continue this line of research but study model checking for first- and monadic second-order logic in the presence of an ordering on the input structure. We do so in two settings: the general ordered case, where the input structures are equipped with a fixed order or successor relation, and the order invariant case, where the formulas may resort to an ordering but their truth must be independent of the particular choice of order. In the first setting we show very strong intractability results for most interesting classes of graphs. In contrast, in order invariant case we obtain tractability results for order invariant monadic second-order logic on the same classes of graphs as in the unordered case. For first-order logic, we obtain tractability of successor-invariant FO on planar graphs.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116017083","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":"Near Unanimity Constraints Have Bounded Pathwidth Duality","authors":"L. Barto, M. Kozik, R. Willard","doi":"10.1109/LICS.2012.24","DOIUrl":"https://doi.org/10.1109/LICS.2012.24","url":null,"abstract":"We show that if a finite relational structure has a near unanimity polymorphism, then the constraint satisfaction problem with that structure as its fixed template has bounded pathwidth duality, putting the problem in nondeterministic logspace. This generalizes the analogous result of Dalmau and Krokhin for majority polymorphisms and lends further support to a conjecture suggested by Larose and Tesson.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131468387","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":"Conservative Concurrency in Haskell","authors":"David Sabel, M. Schmidt-Schauß","doi":"10.1109/LICS.2012.66","DOIUrl":"https://doi.org/10.1109/LICS.2012.66","url":null,"abstract":"The calculus CHF models Concurrent Haskell extended by concurrent, implicit futures. It is a lambda and process calculus with concurrent threads, monadic concurrent evaluation, and includes a pure functional lambda-calculus PF which comprises data constructors, case-expressions, letrec-expressions, and Haskell's seq. Our main result is conservativity of CHF as extension of PF. This allows us to argue that compiler optimizations and transformations from pure Haskell remain valid in Concurrent Haskell even if it is extended by futures. We also show that conservativity does no longer hold if the extension includes Concurrent Haskell and unsafe Interleave IO.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134517720","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":"Functionals Using Bounded Information and the Dynamics of Algorithms","authors":"S. Grigorieff, Pierre Valarcher","doi":"10.1109/LICS.2012.45","DOIUrl":"https://doi.org/10.1109/LICS.2012.45","url":null,"abstract":"We consider computable functionals mapping the Baire space into the set of integers. By continuity, the value of the functional on a given function depends only on a \"critical\" finite part of this function. Care: there is in general no way to compute this critical finite part without querying the function on an arbitrarily larger finite part! Nevertheless, things are different in case there is a uniform bound on the size of the domain of this critical finite part. We prove that, modulo a quadratic blow-up of the bound, one can compute the value of the functional by an algorithm which queries the input function on a uniformly bounded finite part. Up to a constant factor, this quadratic blow-up is optimal. We also characterize such functionals in topological terms using uniformities. As an application of these results, we get a topological characterization of the dynamics of algorithms as modeled by Gurevich's Abstract State Machines.","PeriodicalId":407972,"journal":{"name":"2012 27th Annual IEEE Symposium on Logic in Computer Science","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124417977","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}