Index appearance record with preorders

Jan Kretínský, Tobias Meggendorfer, Clara Waldmann, Maximilian Weininger

Abstract: Transforming $$\omega $$ ω -automata into parity automata is traditionally done using appearance records. We present an efficient variant of this idea, tailored to Rabin automata, and several optimizations applicable to all appearance records. We compare the methods experimentally and show that our method produces significantly smaller automata than previous approaches.