We provide a proof of strong normalisation for lambda+, a recently introduced, explicitly typed, non-deterministic lambda-calculus where isomorphic propositions are identified. Such a proof is a non-trivial adaptation of the reducibility candidates technique.
We define a fragment of propositional logic where isomorphic propositions, such as $A\land B$ and $B\land A$, or $A\Rightarrow (B\land C)$ and $(A\Rightarrow B)\land(A\Rightarrow C)$ are identified. We define System I, a proof language for this logic, and prove its normalisation and consistency.
Continuation-Passing Style and Strong Normalisation for Intuitionistic Sequent Calculi
Curien和Herbelin的λ mu mu-演算的按名称调用版本的直观片段被隔离,并通过嵌入到简单类型的λ mu-演算中来证明其强规范化。我们的嵌入是一个延续和垃圾传递风格的翻译,灵感来自Ikeda和Nakazawa的Parigot的λ\_mu演算的翻译。嵌入严格模拟约简,而通常的连续传递式转换删除置换约简步骤。对于我们的直觉主义微积分,我们甚至只需要传递“垃圾单元”。我们将同样的方法应用于其他演算,即简单类型演算的连续扩展导致我们的直觉系统,并且已经对于我们考虑的最简单的扩展(具有广义应用的演算),这产生了通过约简保持嵌入的强规范化的第一个证明。所得到的结果扩展到第二和更高的阶结石。
This paper studies normalisation by evaluation for typed lambda calculus from a categorical and algebraic viewpoint. The first part of the paper analyses the lambda definability result of Jung and Tiuryn via Kripke logical relations and shows how it can be adapted to unify definability and normalisation, yielding an extensional normalisation result. In the second part of the paper the analysis is refined further by considering intensional Kripke relations (in the form of Artin glueing) and shown to provide a function for normalising terms, casting normalisation by evaluation in the context of …
A key result in the theory of the modal mu-calculus is the disjunctive normal form theorem by Janin & Walukiewicz, stating that every mu-calculus formula is semantically equivalent to a so-called disjunctive formula. These disjunctive formulas have good computational properties and play a pivotal role in the theory of the modal mu-calculus. It is therefore an interesting question what the best normalisation procedure is for rewriting a formula into an equivalent disjunctive formula of minimal size. The best constructions that are known from the literature are automata-theoretic in nature and c…
We present intersection type systems in the style of sequent calculus, modifying the systems that Valentini introduced to prove normalisation properties without using the reducibility method. Our systems are more natural than Valentini's ones and equivalent to the usual natural deduction style systems. We prove the characterisation theorems of strong and weak normalisation through the proposed systems, and, moreover, the approximation theorem by means of direct inductive arguments. This provides in a uniform way proofs of the normalisation and approximation theorems via type systems in sequent…
我们介绍了\emph{resource control cube},一个系统,由八个直观的lambda演算与资源的隐式或显式控制,无论是自然演绎或自然演算。本文介绍了Kesner和Renaud提出的与自然演绎对应的四种立方体演算,以及与λ演算对应的四种立方体演算。该演示文稿是参数化的一组资源(削弱或收缩),这使得一个统一的治疗的八个结石的立方体。简单类型的资源控制立方体一方面将Curry-Howard对应扩展为具有隐式或显式结构规则的直觉自然演绎和直觉推理逻辑,另一方面又与子结构逻辑相关。我们提出了一个通用的交叉型系统的资源控制立方体演算。我们的主要贡献是一个强大的归一化减少在这个立方体的特征。首先,我们证明了可类型性意味着强规范化的“自然演绎基地”的立方体,通过适应reductionmethod。然后,我们证明了可类型性意味着强规范化的“cubes基地”的立方体,通过使用一个组合良好的订单和一个合适的嵌入在“自然演绎基地”。最后,我们证明了强规范化意味着在立方体中使用头部主题扩展的可键入性。所有的证明都是通用的,并且可以通过实例化资源集来针对立方体的每个演算。
超级演绎是一种专门设计的方法,以简化谓词逻辑中一阶理论的使用。运用这一理论,以系统、正确、完整的方式,用新的演绎规则丰富演绎体系。一个证明项语言和一个切消约化已经存在于超演绎中,两者都是基于克里斯蒂安·厄本在经典微积分上的工作。然而,克里斯蒂安·厄本的微积分的计算内容与柯里-霍华德对应(Curry-Howard correspondence)没有直接关系。相反,Lambda bar mu mu波浪线演算是经典波浪线演算的一种波浪线演算。这个简短的文件是第一步,进一步探索的计算内容的superdeduction证明,我们延长了Lambda酒吧亩亩波浪演算,以获得一个proofterm语言一起削减消除减少superdeduction。我们还证明了强大的规范化,这种扩展的λ酒吧亩亩波浪演算。
The infinitary lambda calculi pioneered by Kennaway et al. extend the basic lambda calculus by metric completion to infinite terms and reductions. Depending on the chosen metric, the resulting infinitary calculi exhibit different notions of strictness. To obtain infinitary normalisation and infinitary confluence properties for these calculi, Kennaway et al. extend $β$-reduction with infinitely many `$\bot$-rules', which contract meaningless terms directly to $\bot$. Three of the resulting Böhm reduction calculi have unique infinitary normal forms corresponding to Böhm-like trees. In this paper…
Jeřábek showed that cuts in classical propositional logic proofs in deep inference can be eliminated in quasipolynomial time. The proof is indirect and it relies on a result of Atserias, Galesi and Pudlák about monotone sequent calculus and a correspondence between that system and cut-free deep-inference proofs. In this paper we give a direct proof of Jeřábek's result: we give a quasipolynomial-time cut-elimination procedure for classical propositional logic in deep inference. The main new ingredient is the use of a computational trace of deep-inference proofs called atomic flows, which are bo…
We examine the relationship between the algebraic lambda-calculus, a fragment of the differential lambda-calculus and the linear-algebraic lambda-calculus, a candidate lambda-calculus for quantum computation. Both calculi are algebraic: each one is equipped with an additive and a scalar-multiplicative structure, and their set of terms is closed under linear combinations. However, the two languages were built using different approaches: the former is a call-by-name language whereas the latter is call-by-value; the former considers algebraic equalities whereas the latter approaches them through …
This paper shows that the recent approach to quantitative typing systems for programming languages can be extended to pattern matching features. Indeed, we define two resource aware type systems, named U and E, for a lambda-calculus equipped with pairs for both patterns and terms. Our typing systems borrow some basic ideas from [BKRDR15], which characterises (head) normalisation in a qualitative way, in the sense that typability and normalisation coincide. But in contrast to [BKRDR15], our (static) systems also provides quantitative information about the dynamics of the calculus. Indeed, syste…
We present a novel lambda calculus that casts the categorical approach to the study of quantum protocols into the rich and well established tradition of type theory. Our construction extends the linear typed lambda calculus with a linear negation of "trivialised" De Morgan duality. Reduction is realised through explicit substitution, based on a symmetric notion of binding of global scope, with rules acting on the entire typing judgement instead of on a specific subterm. Proofs of subject reduction, confluence, strong normalisation and consistency are provided, and the language is shown to be a…
This work exploits the logical foundation of session types to determine what kind of type discipline for the pi-calculus can exactly capture, and is captured by, lambda-calculus behaviours. Leveraging the proof theoretic content of the soundness and completeness of sequent calculus and natural deduction presentations of linear logic, we develop the first mutually inverse and fully abstract processes-as-functions and functions-as-processes encodings between a polymorphic session pi-calculus and a linear formulation of System F. We are then able to derive results of the session calculus from the…
System I is a simply-typed lambda calculus with pairs, extended with an equational theory obtained from considering the type isomorphisms as equalities. In this work we propose an extension of System I to polymorphic types, adding the corresponding isomorphisms. We provide non-standard proofs of subject reduction and strong normalisation, extending those of System I.
Since the very beginning of the theory of linear logic it is known how to represent the $λ$-calculus as linear logic proof nets. The two systems however have different granularities, in particular proof nets have an explicit notion of sharing---the exponentials---and a micro-step operational semantics, while the $λ$-calculus has no sharing and a small-step operational semantics. Here we show that the \emph{linear substitution calculus}, a simple refinement of the $λ$-calculus with sharing, is isomorphic to proof nets at the operational level. Nonetheless, two different terms with sharing can s…
In this paper we investigate the $λ$ -calculus, a $λ$-calculus enriched with resource control. Explicit control of resources is enabled by the presence of erasure and duplication operators, which correspond to thinning and con-traction rules in the type assignment system. We introduce directly the class of $λ$ -terms and we provide a new treatment of substitution by its decompo-sition into atomic steps. We propose an intersection type assignment system for $λ$ -calculus which makes a clear correspondence between three roles of variables and three kinds of intersection types. Finally, we provid…
Diagrammatic techniques for reasoning about monoidal categories provide an intuitive understanding of the symmetries and connections of interacting computational processes. In the context of categorical quantum mechanics, Coecke and Kissinger suggested that two 3-qubit states, GHZ and W, may be used as the building blocks of a new graphical calculus, aimed at a diagrammatic classification of multipartite qubit entanglement that would highlight the communicational properties of quantum states, and their potential uses in cryptographic schemes. In this paper, we present a full graphical axiomati…
Faculty of Technical Sciences, University of Novi Sad(诺维萨德大学技术科学学院);Mathematical Institute of the Serbian Academy of Sciences and Arts(塞尔维亚科学院数学研究所);School of Computer Science, University of Birmingham(伯明翰大学计算机学院)
Universidad Nacional de Rosario(罗萨里奥国立大学);Universidad Nacional de Quilmes(基尔梅斯国立大学);Instituto de Investigación en Ciencias de la Computación (ICC), CONICET / Universidad de Buenos Aires(计算机科学研究所(ICC),阿根廷国家科学研究委员会 / 布宜诺斯艾利斯大学)
This paper extends prior work on the connections between logics from finite model theory and propositional/algebraic proof systems. We show that if all non-isomorphic graphs in a given graph class can be distinguished in the logic Choiceless Polynomial Time with counting (CPT), then they can also be distinguished in the bounded-degree extended polynomial calculus (EPC), and the refutations have roughly the same size as the resource consumption of the CPT-sentence. This allows to transfer lower bounds for EPC to CPT and thus constitutes a new potential approach towards better understanding the …
This paper explores the proof theory necessary for recommending an expressive but decidable first-order system, named MAV1, featuring a de Morgan dual pair of nominal quantifiers. These nominal quantifiers called `new' and `wen' are distinct from the self-dual Gabbay-Pitts and Miller-Tiu nominal quantifiers. The novelty of these nominal quantifiers is they are polarised in the sense that `new' distributes over positive operators while `wen' distributes over negative operators. This greater control of bookkeeping enables private names to be modelled in processes embedded as formulae in MAV1. Th…
This paper deals with retraction - intended as isomorphic embedding - in intersection types building left and right inverses as terms of a lambda calculus with a bottom constant. The main result is a necessary and sufficient condition two strict intersection types must satisfy in order to assure the existence of two terms showing the first type to be a retract of the second one. Moreover, the characterisation of retraction in the standard intersection types is discussed.
The good properties of Plotkin's call-by-value lambda-calculus crucially rely on the restriction to weak evaluation and closed terms. Open call-by-value is the more general setting where evaluation is weak but terms may be open. Such an extension is delicate, and the literature contains a number of proposals. Recently, Accattoli and Guerrieri provided detailed operational and implementative studies of these proposals, showing that they are equivalent from the point of view of termination, and also at the level of time cost models. This paper explores the denotational semantics of open call-by-…
Université de Lorraine, CNRS, Inria, LORIA(洛林大学、法国国家科学研究中心、Inria、LORIA);InCo, FIng, Universidad de la República(乌拉圭共和国大学工程与计算机学院);DC, FCEN, Universidad de Buenos Aires(布宜诺斯艾利斯大学理学院)
We propose an implementation of lambda+, a recently introduced simply typed lambda-calculus with pairs where isomorphic types are made equal. The rewrite system of lambda+ is a rewrite system modulo an equivalence relation, which makes its implementation non-trivial. We also extend lambda+ with natural numbers and general recursion and use Bekić's theorem to split mutual recursions. This splitting, together with the features of lambda+, allows for a novel way of program transformation by reduction, by projecting a function before it is applied in order to simplify it. Also, currying together w…
Lambda calculi with algebraic data types lie at the core of functional programming languages and proof assistants, but conceal at least two fundamental theoretical problems already in the presence of the simplest non-trivial data type, the sum type. First, we do not know of an explicit and implemented algorithm for deciding the beta-eta-equality of terms---and this in spite of the first decidability results proven two decades ago. Second, it is not clear how to decide when two types are essentially the same, i.e. isomorphic, in spite of the meta-theoretic results on decidability of the isomorp…
This volume contains a final and revised selection of papers presented at the Seventh Workshop on Intersection Types and Related Systems (ITRS 2014), held in Vienna (Austria) on July 18th, affiliated with TLCA 2014, Typed Lambda Calculi and Applications (held jointly with RTA, Rewriting Techniques and Applications) as part of FLoC and the Vienna Summer of Logic (VSL) 2014. Intersection types have been introduced in the late 1970s as a language for describing properties of lambda calculus which were not captured by all previous type systems. They provided the first characterisation of strongly …