sweap: Reactive Synthesis for Infinite-State Integer Problems

2026-05-12

AI Summary

This work addresses the synthesis problem for reactive systems under infinite-state integer arithmetic, tackling key challenges such as the difficulty of proving unrealizability, restrictive variable initialization assumptions, and limited expressiveness in update operations. To overcome these limitations, the authors propose a counterexample-guided abstraction refinement (CEGAR)-based dual abstraction mechanism that reduces the original infinite-state problem to finite-state subproblems amenable to existing black-box finite-state synthesis tools. The approach supports nondeterministic and unbounded variable updates, general initialization conditions, and preserves realizability equivalence through sound abstractions. Experimental evaluation demonstrates that the implemented tool, sweap, significantly outperforms the only existing competing method in both scalability and solving efficiency.

Abstract

Recent years have seen a significant increase in the interest in reactive synthesis from specifications that relate to infinite state spaces. We present sweap, a tool for synthesis of infinite-state Linear Integer Arithmetic reactive systems. sweap implements a CEGAR approach, relying on state-of-the-art finite-state synthesis tools as black boxes to solve abstract synthesis problems. sweap supports most common input formalisms for infinite-state reactive-synthesis problems: Temporal Stream Logic Modulo Theories, Reactive Program Games, the bespoke input of the ISSY tool, and our own bespoke input. We present a mature version of sweap with novel features: a dual abstraction approach that improves its capabilities in proving unrealisability, support for nondeterministic and unbounded updates, more general initialization of variables, and equirealisable reductions for optimisation. Experimental evaluation shows that sweap outperforms its only competitor in this domain.

Problem

• reactive synthesis
• infinite-state
• Linear Integer Arithmetic
• unrealisability
• Temporal Stream Logic Modulo Theories

Innovation

• reactive synthesis
• infinite-state systems
• CEGAR
• Linear Integer Arithmetic
• unrealisability