arXiv subjects

Philippe Heim

Publications and source records attributed to Philippe Heim.

8 recordsLinked to original sources

arXiv2026

Modular Attractor Acceleration in Infinite-State Games (Full Version)

Infinite-state games provide a framework for the synthesis of reactive systems with unbounded data domains. Solving such games typically relies on computing symbolic fixpoints, particularly symbolic attractors. However, these computations may not terminate, and while recent acceleration techniques have been proposed to address this issue, they often rely on acceleration arguments of limited expressiveness. In this work, we propose an approach for the modular computation of acceleration arguments. It enables the construction of complex acceleration arguments by composing simpler ones, thereby improving both scalability and flexibility. In addition, we introduce a summarization technique that generalizes discovered acceleration arguments, allowing them to be efficiently reused across multiple contexts. Together, these contributions improve the efficiency of solving infinite-state games in reactive synthesis, as demonstrated by our experimental evaluation.

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arXiv2025

Issy: A Comprehensive Tool for Specification and Synthesis of Infinite-State Reactive Systems

The synthesis of infinite-state reactive systems from temporal logic specifications or infinite-state games has attracted significant attention in recent years, leading to the emergence of novel solving techniques. Most approaches are accompanied by an implementation showcasing their viability on an increasingly larger collection of benchmarks. Those implementations are -- often simple -- prototypes. Furthermore, differences in specification formalisms and formats make comparisons difficult, and writing specifications is a tedious and error-prone task. To address this, we present Issy, a tool for specification, realizability, and synthesis of infinite-state reactive systems. Issy comes with an expressive specification language that allows for combining infinite-state games and temporal formulas, thus encompassing the current formalisms. The realizability checking and synthesis methods implemented in Issy build upon recently developed approaches and extend them with newly engineered efficient techniques, offering a portfolio of solving algorithms. We evaluate Issy on an extensive set of benchmarks, demonstrating its competitiveness with the state of the art. Furthermore, Issy provides tooling for a general high-level format designed to make specification easier for users. It also includes a compiler to a more machine-readable format that other tool developers can easily use, which we hope will lead to a broader adoption and advances in infinite-state reactive synthesis.

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arXiv2024

Translation of Temporal Logic for Efficient Infinite-State Reactive Synthesis (Full Version)

Infinite-state reactive synthesis has attracted significant attention in recent years, which has led to the emergence of novel symbolic techniques for solving infinite-state games. Temporal logics featuring variables over infinite domains offer an expressive high-level specification language for infinite-state reactive systems. Currently, the only way to translate these temporal logics into symbolic games is by naively encoding the specification to use techniques designed for the Boolean case. An inherent limitation of this approach is that it results in games in which the semantic structure of the temporal and first-order constraints present in the formula is lost. There is a clear need for techniques that leverage this information in the translation process to speed up solving the generated games. In this work, we propose the first approach that addresses this gap. Our technique constructs a monitor incorporating first-order and temporal reasoning at the formula level, enriching the constructed game with semantic information that leads to more efficient solving. We demonstrate that thanks to this, our method outperforms the state-of-the-art techniques across a range of benchmarks.

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arXiv2024

Localized Attractor Computations for Infinite-State Games (Full Version)

Infinite-state games are a commonly used model for the synthesis of reactive systems with unbounded data domains. Symbolic methods for solving such games need to be able to construct intricate arguments to establish the existence of winning strategies. Often, large problem instances require prohibitively complex arguments. Therefore, techniques that identify smaller and simpler sub-problems and exploit the respective results for the given game-solving task are highly desirable. In this paper, we propose the first such technique for infinite-state games. The main idea is to enhance symbolic game-solving with the results of localized attractor computations performed in sub-games. The crux of our approach lies in identifying useful sub-games by computing permissive winning strategy templates in finite abstractions of the infinite-state game. The experimental evaluation of our method demonstrates that it outperforms existing techniques and is applicable to infinite-state games beyond the state of the art.

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arXiv2023

Solving Infinite-State Games via Acceleration (Full Version)

Two-player graph games have found numerous applications, most notably in the synthesis of reactive systems from temporal specifications, but also in verification. The relevance of infinite-state systems in these areas has lead to significant attention towards developing techniques for solving infinite-state games. We propose novel symbolic semi-algorithms for solving infinite-state games with temporal winning conditions. The novelty of our approach lies in the introduction of an acceleration technique that enhances fixpoint-based game-solving methods and helps to avoid divergence. Classical fixpoint-based algorithms, when applied to infinite-state games, are bound to diverge in many cases, since they iteratively compute the set of states from which one player has a winning strategy. Our proposed approach can lead to convergence in cases where existing algorithms require an infinite number of iterations. This is achieved by acceleration: computing an infinite set of states from which a simpler sub-strategy can be iterated an unbounded number of times in order to win the game. Ours is the first method for solving infinite-state games to employ acceleration. Thanks to this, it is able to outperform state-of-the-art techniques on a range of benchmarks, as evidenced by our evaluation of a prototype implementation.

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arXiv2023

Taming Large Bounds in Synthesis from Bounded-Liveness Specifications (Full Version)

Automatic synthesis from temporal logic specifications is an attractive alternative to manual system design, due to its ability to generate correct-by-construction implementations from high-level specifications. Due to the high complexity of the synthesis problem, significant research efforts have been directed at developing practically efficient approaches for restricted specification language fragments. In this paper, we focus on the Safety LTL fragment of Linear Temporal Logic (LTL) syntactically extended with bounded temporal operators. We propose a new synthesis approach with the primary motivation to solve efficiently the synthesis problem for specifications with bounded temporal operators, in particular those with large bounds. The experimental evaluation of our method shows that for this type of specifications, it outperforms state-of-art synthesis tools, demonstrating that it is a promising approach to efficiently treating quantitative timing constraints in safety specifications.

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arXiv2021

Temporal Stream Logic modulo Theories (Full Version)

Temporal stream logic (TSL) extends LTL with updates and predicates over arbitrary function terms. This allows for specifying data-intensive systems for which LTL is not expressive enough. In the semantics of TSL, functions and predicates are left uninterpreted. In this paper, we extend TSL with first-order theories, enabling us to specify systems using interpreted functions and predicates such as incrementation or equality. We investigate the satisfiability problem of TSL modulo the standard underlying theory of uninterpreted functions as well as with respect to Presburger arithmetic and the theory of equality: For all three theories, TSL satisfiability is highly undecidable. Nevertheless, we identify three fragments of TSL for which the satisfiability problem is (semi-)decidable in the theory of uninterpreted functions. Despite the high undecidability, we present an algorithm - which is not guaranteed to terminate - for checking the satisfiability of a TSL formula in the theory of uninterpreted functions and evaluate it: It scales well and is able to validate assumptions in a real-world system design.

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arXiv2021

Syntroids: Synthesizing a Game for FPGAs using Temporal Logic Specifications

We present Syntroids, a case study for the automatic synthesis of hardware from a temporal logic specification. Syntroids is a space shooter arcade game realized on an FPGA, where the control flow architecture has been completely specified in Temporal Stream Logic (TSL) and implemented using reactive synthesis. TSL is a recently introduced temporal logic that separates control and data. This leads to scalable synthesis, because the cost of the synthesis process is independent of the complexity of the handled data. In this case study, we report on our experience with the TSL-based development of the Syntroids game and on the implementation quality obtained with synthesis in comparison to manual programming. We also discuss solved and open challenges with respect to currently available synthesis tools.

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