Indexed linear logic and higher-order model checking

In recent work, Kobayashi observed that the acceptance by an alternating tree automaton A of an infinite tree T generated by a higher-order recursion scheme G may be formulated as the typability of the recursion scheme G in an appropriate intersection type system associated to the automaton A. The purpose of this article is to establish a clean connection between this line of work and Bucciarelli and Ehrhard's indexed linear logic. This is achieved in two steps. First, we recast Kobayashi's result in an equivalent infinitary intersection type system where intersection is not idempotent anymore. Then, we show that the resulting type system is a fragment of an infinitary version of Bucciarelli and Ehrhard's indexed linear logic. While this work is very preliminary and does not integrate key ingredients of higher-order model-checking like priorities, it reveals an interesting and promising connection between higher-order model-checking and linear logic.Comment: In Proceedings ITRS 2014, arXiv:1503.0437

Asynchronous games 4 : A fully complete model of propositional linear logic

International audienceWe construct a denotational model of propositional linear logic based on asynchronous games and winning uniform innocent strategies. Every formula A is interpreted as an asynchronous game [A] and every proof pi of A is interpreted as a winning uniform innocent strategy pi of the game A. We show that the resulting model is fully complete: every winning uniform innocent strategy sigma of the asynchronous game A is the denotation pi of a proof pi of the formula A

A topological correctness criterion for non-commutative logic

We formulate Girard's long trip criterion for multiplicative linear logic (MLL) in a topological way, by associating a ribbon diagram to every switching, and requiring that it is homeomorphic to the disk. Then, we extend the well-known planarity criterion for multiplicative cyclic linear logic (McyLL) to multiplicative non-commutative logic (MNL) and show that the resulting planarity criterion is equivalent to Abrusci and Ruet's original long trip criterion for MNL

Resource modalities in game semantics

The description of resources in game semantics has never achieved the simplicity and precision of linear logic, because of a misleading conception: the belief that linear logic is more primitive than game semantics. We advocate instead the contrary: that game semantics is conceptually more primitive than linear logic. Starting from this revised point of view, we design a categorical model of resources in game semantics, and construct an arena game model where the usual notion of bracketing is extended to multi- bracketing in order to capture various resource policies: linear, affine and exponential

Asynchronous games 2: the true concurrency of innocence

In game semantics, the higher-order value passing mechanisms of the lambda-calculus are decomposed as sequences of atomic actions exchanged by a Player and its Opponent. Seen from this angle, game semantics is reminiscent of trace semantics in concurrency theory, where a process is identified to the sequences of requests it generates in the course of time. Asynchronous game semantics is an attempt to bridge the gap between the two subjects, and to see mainstream game semantics as a refined and interactive form of trace semantics. Asynchronous games are positional games played on Mazurkiewicz traces, which reformulate (and generalize) the familiar notion of arena game. The interleaving semantics of lambda-terms, expressed as innocent strategies, may be analyzed in this framework, in the perspective of true concurrency. The analysis reveals that innocent strategies are positional strategies regulated by forward and backward confluence properties. This captures, we believe, the essence of innocence. We conclude the article by defining a non uniform variant of the lambda-calculus, in which the game semantics of a lambda-term is formulated directly as a trace semantics, performing the syntactic exploration or parsing of that lambda-term

Sequential algorithms and strongly stable functions

International audienceIntuitionistic proofs (or PCF programs) may be interpreted as functions between domains, or as strategies on games. The two kinds of interpretation are inherently different: static vs. dynamic, extensional vs. intentional. It is extremely instructive to compare and to connect them. In this article, we investigate the extensional content of the sequential algorithm hierarchy [-] introduced by Berry and Curien two decades ago. We equip every sequential game [T] of the hierarchy with a realizability relation between plays and extensions. In this way, the sequential game [T] becomes a directed acyclic graph, instead of a tree. This enables to define a hypergraph [[T]] on the extensions (or terminal leaves) of the game [T]. We establish that the resulting hierarchy [[T]] coincides with the strongly stable hierarchy introduced by Bucciarelli and Ehrhard. We deduce from this a game-theoretic proof of Ehrhard's collapse theorem, which states that the strongly stable hierarchy coincides with the extensional collapse of the sequential algorithm hierarchy

Mac Lane's coherence theorem expressed as a word problem

manuscrit de 10 pagesIn this manuscript, we reduce the coherence theorem for braided monoidal categories to the resolution of a word problem, and the construction of a category of fractions. The technique explicates the combinatorial nature of that particular coherence theorem