Computing Lower and Upper Hitting Probabilities for Imprecise Markov Chains

Fuente: arXiv
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Auteurs principaux: Sangalli, Marco, Quaeghebeur, Erik, Krak, Thomas
Format: Preprint
Publié: 2025
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author Sangalli, Marco
Quaeghebeur, Erik
Krak, Thomas
author_facet Sangalli, Marco
Quaeghebeur, Erik
Krak, Thomas
contents We study the computation of lower and upper probabilities of hitting a target set of states for imprecise Markov chains, where transition uncertainty is modelled by a convex set of transition matrices. In the precise case, hitting probabilities are the minimal nonnegative solution of a linear system and admit a closed-form expression. We investigate the notion of reachability in the imprecise setting. The literature review highlights several different definitions of lower reachability; thus, we explore the relations among them and present examples to clarify their logical implications. Using this revised definition of reachability for imprecise Markov chains, we partition the state space into classes of states whose hitting probabilities are trivially zero or one, and those which require further computation. For these nontrivial states, we show that the lower hitting probability is the unique solution of a nonlinear fixed-point equation, while the same does not hold for upper hitting probabilities. For the practical computation of lower and upper hitting probabilities, we propose iterative algorithms that alternate between solving a linear system and choosing an extreme point from the set of transition matrices. Numerical experiments demonstrate that, in practice, these algorithms converge in substantially fewer iterations than the theoretically established worst-case bound.
format Preprint
id arxiv_https___arxiv_org_abs_2512_16696
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Computing Lower and Upper Hitting Probabilities for Imprecise Markov Chains
Sangalli, Marco
Quaeghebeur, Erik
Krak, Thomas
Probability
We study the computation of lower and upper probabilities of hitting a target set of states for imprecise Markov chains, where transition uncertainty is modelled by a convex set of transition matrices. In the precise case, hitting probabilities are the minimal nonnegative solution of a linear system and admit a closed-form expression. We investigate the notion of reachability in the imprecise setting. The literature review highlights several different definitions of lower reachability; thus, we explore the relations among them and present examples to clarify their logical implications. Using this revised definition of reachability for imprecise Markov chains, we partition the state space into classes of states whose hitting probabilities are trivially zero or one, and those which require further computation. For these nontrivial states, we show that the lower hitting probability is the unique solution of a nonlinear fixed-point equation, while the same does not hold for upper hitting probabilities. For the practical computation of lower and upper hitting probabilities, we propose iterative algorithms that alternate between solving a linear system and choosing an extreme point from the set of transition matrices. Numerical experiments demonstrate that, in practice, these algorithms converge in substantially fewer iterations than the theoretically established worst-case bound.
title Computing Lower and Upper Hitting Probabilities for Imprecise Markov Chains
topic Probability
url https://arxiv.org/abs/2512.16696