Realizable and Context-Free Hyperlanguages

Autor: Frenkel, Hadar, Sheinvald, Sarai
Rok vydání: 2022
Předmět:
Zdroj: EPTCS 370, 2022, pp. 114-130
Druh dokumentu: Working Paper
DOI: 10.4204/EPTCS.370.8
Popis: Hyperproperties lift conventional trace-based languages from a set of execution traces to a set of sets of executions. From a formal-language perspective, these are sets of sets of words, namely hyperlanguages. Hyperautomata are based on classical automata models that are lifted to handle hyperlanguages. Finite hyperautomata (NFH) have been suggested to express regular hyperproperties. We study the realizability problem for regular hyperlanguages: given a set of languages, can it be precisely described by an NFH? We show that the problem is complex already for singleton hyperlanguages. We then go beyond regular hyperlanguages, and study context-free hyperlanguages. We show that the natural extension to context-free hypergrammars is highly undecidable. We then suggest a refined model, namely synchronous hypergrammars, which enables describing interesting non-regular hyperproperties, while retaining many decidable properties of context-free grammars.
Comment: In Proceedings GandALF 2022, arXiv:2209.09333
Databáze: arXiv