Abstract
Bisimilarity is a central notion for coalgebras. In recent work, Geuvers and Jacobs suggest to focus on apartness, which they define by dualising coalgebraic bisimulations. This yields the possibility of finite proofs of distinguishability for a wide variety of state-based systems.
We propose behavioural apartness, defined by dualising behavioural equivalence rather than bisimulations. A motivating example is the subdistribution functor, where the proof system based on bisimilarity requires an infinite quantification over couplings, whereas behavioural apartness instantiates to a finite rule. In addition, we provide optimised proof rules for behavioural apartness and show their use in several examples.
This research is partially supported by the NWO grant No. OCENW.M20.053, the EPSRC NIA Grant EP/X019373/1, and the Royal Society Travel Grant IES\(\backslash \) R3\(\backslash \)223092 and the Leverhulme Trust Research Project Grant RPG-2020-232.
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Turkenburg, R., Beohar, H., Kupke, C., Rot, J. (2024). Proving Behavioural Apartness. In: König, B., Urbat, H. (eds) Coalgebraic Methods in Computer Science. CMCS 2024. Lecture Notes in Computer Science, vol 14617. Springer, Cham. https://doi.org/10.1007/978-3-031-66438-0_8
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