We propose a flexible exchange format for ω-automata, as typically used in formal verification, and implement support for it in a range of established tools. Our aim is to simplify the interaction of tools, helping the research community to build upon other people's work. A key feature of the format is the use of very generic acceptance conditions, specified by Boolean combinations of acceptance primitives, rather than being limited to common cases such as Büchi, Streett, or Rabin. Such flexibility in the choice of acceptance conditions can be exploited in applications, for example in probabilistic model checking, and furthermore encourages the development of acceptance-agnostic tools for automata manipulations. The format allows acceptance conditions that are either state-based or transition-based, and also supports alternating automata.

No abstract

Some applications of linear temporal logic (LTL) require to translate formulae of the logic to deterministic ω-automata. There are currently two translators producing deterministic automata: ltl2dstar working for the whole LTL and Rabinizer applicable to LTL(F, G) which is the LTL fragment using only modalities F and G. We present a new translation to deterministic Rabin automata via alternating automata and deterministic transition-based generalized Rabin automata. Our translation applies to a fragment that is strictly larger than LTL(F, G). Experimental results show that our algorithm can produce significantly smaller automata compared to Rabinizer and ltl2dstar, especially for more complex LTL formulae.

We present the second generation of the tool Seminator that transforms transition-based generalized Büchi automata (TGBAs) into equivalent semi-deterministic automata. The tool has been extended with numerous optimizations and produces considerably smaller automata than its first version. In connection with the state-of-the-art LTL to TGBAs translator Spot, Seminator 2 produces smaller (on average) semi-deterministic automata than the direct LTL to semi-deterministic automata translator ltl2ldgba of the Owl library. Further, Seminator 2 has been extended with an improved NCSB complementation procedure for semi-deterministic automata, providing a new way to complement automata that is competitive with state-of-the-art complementation tools.

We present a tool that transforms nondeterministic ω-automata to semi-deterministic ω-automata. The tool Seminator accepts transition-based generalized Büchi automata (TGBA) as an input and produces automata with two kinds of semi-determinism. The implemented procedure performs degeneralization and semi-determinization simultaneously and employs several other optimizations. We experimentally evaluate Seminator in the context of LTL to semi-deterministic automata translation.