Capturing Bisimulation-Invariant Exponential-Time Complexity Classes
Abstract
Otto's Theorem characterises the bisimulation-invariant PTIME queries over graphs as exactly those that can be formulated in the polyadic mu-calculus, hinging on the Immerman-Vardi Theorem which characterises PTIME (over ordered structures) by First-Order Logic with least fixpoints. This connection has been extended to characterise bisimulation-invariant EXPTIME by an extension of the polyadic mu-calculus with functions on predicates, making use of Immerman's characterisation of EXPTIME by Second-Order Logic with least fixpoints. In this paper we show that the bisimulation-invariant versions of all classes in the exponential time hierarchy have logical counterparts which arise as extensions of the polyadic mu-calculus by higher-order functions. This makes use of the characterisation of k-EXPTIME by Higher-Order Logic (of order k+1) with least fixpoints, due to Freire and Martins.
Cite
@article{arxiv.2209.10311,
title = {Capturing Bisimulation-Invariant Exponential-Time Complexity Classes},
author = {Florian Bruse and David Kronenberger and Martin Lange},
journal= {arXiv preprint arXiv:2209.10311},
year = {2022}
}
Comments
In Proceedings GandALF 2022, arXiv:2209.09333