一句话:用事件结构统一构造 Spoiler-Duplicator 博弈余单子,并刻画一/双侧博弈策略。
Spoiler-Duplicator 博弈是有限模型论中研究逻辑表达力的工具,近期其策略被重述为关系结构上博弈余单子的 coKleisli 映射。本文提出以事件结构为统一视角的新框架:将博弈视为事件结构,并首次系统地从博弈模式(signature games)双范畴中的余单子经由到博弈范畴的伴随来构造余单子,从而覆盖所有单侧 Spoiler-Duplicator 博弈。所构造博弈范畴中的映射即策略,推广了博弈余单子的 coKleisli 映射;对单侧博弈,这些策略恰与适当广义化的同态一致。文章还刻画了双侧博弈的策略,并证明在常见特殊情形下它们与事件结构的 span 一致。
Spoiler-Duplicator games are used in finite model theory to examine the expressive power of logics. Their strategies have recently been reformulated as coKleisli maps of game comonads over relational structures, providing new results in finite model theory via categorical techniques. We present a novel framework for studying Spoiler-Duplicator games by viewing them as event structures. We introduce a first systematic method for constructing comonads for all one-sided Spoiler-Duplicator games: game comonads are now realised by adjunctions to a category of games, generically constructed from a comonad in a bicategory of game schema (called signature games). Maps of the constructed categories of games are strategies and generalise coKleisli maps of game comonads; in the case of one-sided games they are shown to coincide with suitably generalised homomorphisms. Finally, we provide characterisations of strategies on two-sided Spoiler-Duplicator games; in a common special case they coincide with spans of event structures.