| Title | A logic for suspicious players: epistemic actions and belief-updates in games |
| Publication Type | Book Chapter |
| Year of Publication | 2000 |
| Authors | Baltag A |
| Book Title | 906 |
| Pagination | 33 |
| Publisher | Centrum voor Wiskunde en Informatica (CWI) |
| City | ISSN 1386-369X |
| Keywords | belief change, communication, distributed systems, dynamic logic, epistemic action, epistemic logic, games, information update, learning, muddy children puzzle |
| Abstract | In this paper, we introduce a notion of ``epistemic action'' to describe changes in the information states of the players in a game. For this, we use ideas that we have developed in our previous papers [BMS], [BMS2] and [B], enriching them to cover, not just ıt purely epistemic} actions, but also ıt fact-changing actions} (``real moves'', e.g. choosing a card, exchanging cards etc.) and ıt nondeterministic actions} and ıt strategies} (conditional actions having knowledge tests as conditions). We consider natural ıt operations with epistemic actions} and we use them to describe significant aspects of the interaction between beliefs and actions in a game. For this, we use a logic that combines in a specific way a multi-agent epistemic logic with a dynamic logic of ``epistemic actions''. We give (without proof) ıt a complete and decidable proof system} for this logic. As an application, we analyze a specific example of a dialogue game (a version of the Muddy Children Puzzle, in which some of the children can ``cheat'' by engaging in secret communication moves, while others may be punished for their credulity). We also present a sketch of a ``rule-based'' approach to games with imperfect information (allowing ``sneaky'' possibilities, such as: cheating, being deceived and suspecting the others to be cheating). |
| URL | http://www.cwi.nl/ftp/CWIreports/SEN/SEN-R0044.ps.Z |