Introduction

This website explains the phenomenon of common knowledge in different variants. This form of knowledge is a very important issue in everyday life. Sometimes it is not possible to obtain common knowledge about some fact. We show that in these cases, we can suffice with a somewhat milder form of common knowledge, which is called shared knowledge.
 
Some examples of this phenomenon will be described and visualized. We start with the Ann and Bob example, which describes an everyday situation in which we make use of common knowledge. After that, the Byzantine Generals puzzle is described, in which common knowledge can never be achieved. Finally, the Alice & John example is described, in which time plays an important role in their communication. With these examples, we can explain the concept of common knowledge versus shared knowledge in the next three chapters.
 
This website is made as a project for a course in Multi Agent Systems. This course concentrates on the logic of knowledge and belief. A basic logical approach is made on epistemic and modal logic. This approach is being used to look at problems concerning computer science and artificial intelligence, like the characterisation of a state of knowledge of an agent in a system.
 
Enjoy!
 
Harrie de Groot
Jan Gerard Gerrits
 
 
P.S. You need Adobe Flash Player to use the interactive movies on this web page. The player can be downloaded from http://www.adobe.com/shockwave/download

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