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Automaton-Based Representations of Task Knowledge from Generative Language Models
Proceedings of the International Conference on Neuro-symbolic Systems, PMLR 288:765-783, 2025.
Abstract
Automaton-based representations play an important role in control and planning for sequential decision-making problems. However, obtaining the high-level task knowledge required to build such automata is often difficult. Meanwhile, generated language models (GLMs) can automatically generate relevant text-based task knowledge. However, such text-based knowledge cannot be formally verified or used for sequential decision-making. We propose a novel algorithm named GLM2FSA that constructs a finite state automaton (FSA) encoding high-level task knowledge from a brief natural-language description of the task goal. GLM2FSA first sends queries to a GLM to extract task knowledge in textual form, and then it builds an FSA to represent this text-based knowledge. The proposed algorithm thus fills the gap between natural-language task descriptions and automaton-based representations, and the constructed FSAs can be formally verified against user-defined specifications. We accordingly propose a procedure to iteratively refine the input queries to the GLM based on the outcomes, e.g., counter-examples, from verification. We apply the proposed algorithm to an autonomous driving system to demonstrate its capability for sequential decision-making and formal verification. Furthermore, quantitative results indicate the refinement method improves the probability of generated knowledge satisfying the specifications by 40 percent.