Playing Stochastically in Weighted Timed Games to Emulate Memory

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...

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Main Authors: Benjamin Monmege, Julie Parreaux, Pierre-Alain Reynier
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2025-02-01
Series:Logical Methods in Computer Science
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Online Access:http://lmcs.episciences.org/10993/pdf
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author Benjamin Monmege
Julie Parreaux
Pierre-Alain Reynier
author_facet Benjamin Monmege
Julie Parreaux
Pierre-Alain Reynier
author_sort Benjamin Monmege
collection DOAJ
description 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.
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spelling doaj-art-e1a9a3bec1ae44f0aa579fd9be8203522025-08-20T03:42:35ZengLogical Methods in Computer Science e.V.Logical Methods in Computer Science1860-59742025-02-01Volume 21, Issue 110.46298/lmcs-21(1:19)202510993Playing Stochastically in Weighted Timed Games to Emulate MemoryBenjamin MonmegeJulie ParreauxPierre-Alain ReynierWeighted 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.http://lmcs.episciences.org/10993/pdfcomputer science - computer science and game theory
spellingShingle Benjamin Monmege
Julie Parreaux
Pierre-Alain Reynier
Playing Stochastically in Weighted Timed Games to Emulate Memory
Logical Methods in Computer Science
computer science - computer science and game theory
title Playing Stochastically in Weighted Timed Games to Emulate Memory
title_full Playing Stochastically in Weighted Timed Games to Emulate Memory
title_fullStr Playing Stochastically in Weighted Timed Games to Emulate Memory
title_full_unstemmed Playing Stochastically in Weighted Timed Games to Emulate Memory
title_short Playing Stochastically in Weighted Timed Games to Emulate Memory
title_sort playing stochastically in weighted timed games to emulate memory
topic computer science - computer science and game theory
url http://lmcs.episciences.org/10993/pdf
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AT julieparreaux playingstochasticallyinweightedtimedgamestoemulatememory
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