Playing Stochastically in Weighted Timed Games to Emulate Memory

Fuente: arXiv
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Main Authors: Monmege, Benjamin, Parreaux, Julie, Reynier, Pierre-Alain
Format: Preprint
Published: 2021
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author Monmege, Benjamin
Parreaux, Julie
Reynier, Pierre-Alain
author_facet Monmege, Benjamin
Parreaux, Julie
Reynier, Pierre-Alain
contents Weighted timed games are two-player zero-sum games played in a timed automaton equipped with integer weights. We consider optimal reachability objectives, in which one of the players, that we call Min, wants to reach a target location while minimising the cumulated weight. While knowing if Min has a strategy to guarantee a value lower than a given threshold is known to be undecidable (with two or more clocks), several conditions, one of them being divergence, have been given to recover decidability. In such weighted timed games (like in untimed weighted games in the presence of negative weights), Min may need finite memory to play (close to) optimally. This is thus tempting to try to emulate this finite memory with other strategic capabilities. In this work, we allow the players to use stochastic decisions, both in the choice of transitions and of timing delays. We give a definition of the expected value in weighted timed games. We then show that, in divergent weighted timed games as well as in (untimed) weighted games (that we call shortest-path games in the following), the stochastic value is indeed equal to the classical (deterministic) value, thus proving that Min can guarantee the same value while only using stochastic choices, and no memory.
format Preprint
id arxiv_https___arxiv_org_abs_2105_00984
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Playing Stochastically in Weighted Timed Games to Emulate Memory
Monmege, Benjamin
Parreaux, Julie
Reynier, Pierre-Alain
Computer Science and Game Theory
Weighted timed games are two-player zero-sum games played in a timed automaton equipped with integer weights. We consider optimal reachability objectives, in which one of the players, that we call Min, wants to reach a target location while minimising the cumulated weight. While knowing if Min has a strategy to guarantee a value lower than a given threshold is known to be undecidable (with two or more clocks), several conditions, one of them being divergence, have been given to recover decidability. In such weighted timed games (like in untimed weighted games in the presence of negative weights), Min may need finite memory to play (close to) optimally. This is thus tempting to try to emulate this finite memory with other strategic capabilities. In this work, we allow the players to use stochastic decisions, both in the choice of transitions and of timing delays. We give a definition of the expected value in weighted timed games. We then show that, in divergent weighted timed games as well as in (untimed) weighted games (that we call shortest-path games in the following), the stochastic value is indeed equal to the classical (deterministic) value, thus proving that Min can guarantee the same value while only using stochastic choices, and no memory.
title Playing Stochastically in Weighted Timed Games to Emulate Memory
topic Computer Science and Game Theory
url https://arxiv.org/abs/2105.00984