A Stay-in-a-Set Game without a Stationary Equilibrium Mikhail Raskin - - PowerPoint PPT Presentation

a stay in a set game without a stationary equilibrium
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A Stay-in-a-Set Game without a Stationary Equilibrium Mikhail Raskin - - PowerPoint PPT Presentation

A Stay-in-a-Set Game without a Stationary Equilibrium Mikhail Raskin , raskin@mccme.ru 1 Kristoffer Arnsfelt Hansen September 3, 2019 1 The author has received funding from ERC under the EU H2020 programme grant No 787367 (PaVeS) and from the


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A Stay-in-a-Set Game without a Stationary Equilibrium

Kristoffer Arnsfelt Hansen Mikhail Raskin, raskin@mccme.ru 1 September 3, 2019

1The author has received funding from ERC under the EU H2020 programme grant

No 787367 (PaVeS) and from the ANR project GraphEn / ANR-15-CE40-0009.

  • K. A. Hansen & M. Raskin

Stay-in-Set Game without Stationary NE September 3, 2019 1 / 11

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Setting

Turn-based (perfect information) Finite Stochastic Independent safety goals

  • K. A. Hansen & M. Raskin

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Secchi, Sudderth 2002

Exact Nash equilibrium exists with bounded memory Remember who has lost

  • K. A. Hansen & M. Raskin

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Existence proof: overview

Induction 1 player: Markov decision process Arbitrary positional strategy for each player in case of loss Uniform bound on time until someone loses or loss becomes impossible Payoffs at that point: by inductive assumption (or obvious)

  • K. A. Hansen & M. Raskin

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Question

For 2 players, is there always zero memory Nash equilibrium (instead

  • f 2 bits of memory)?

(i.e. equilibrium in stationary strategies)

  • K. A. Hansen & M. Raskin

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Similar questions

Discounted payoffs: stationary equilibrium Deterministic game: stationary equilibrium Recursive/imperfect information games: no stationary ε-Nash equilibrium

  • K. A. Hansen & M. Raskin

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Example without stationary equilibrium

1 2 L2 W L c q 1/4 1/2 1/4 c q 1/4 3/4 1/4 1/4 1/2

  • K. A. Hansen & M. Raskin

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Example without stationary equilibrium: incentives

If cycle is left, both P1 and P2 prefer that P1 leaves For P1 best case is staying For P2 staying means loss Note that ε-equilibrium exists

  • K. A. Hansen & M. Raskin

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Open questions

(for two players) Stationary ε-equilibrium? Stationary equilibrium for reachability conditions? Stationary equilibrium for deterministic recursive games with reachability conditions?

  • K. A. Hansen & M. Raskin

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Thanks for your attention! Questions?

  • K. A. Hansen & M. Raskin

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Summary

Discounted payoffs: stationary equilibrium Deterministic game: stationary equilibrium Recursive/imperfect information games: no stationary ε-Nash equilibrium Two-player turn-based stay-in-a-set game: no stationary equilibrium Stationary ε-equilibrium? Stationary equilibrium for reachability conditions? Stationary equilibrium for deterministic recursive games with reachability conditions?

  • K. A. Hansen & M. Raskin

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