Reasoning about Information Update: 20112012
Lecturer 

Degrees 
Schedule B2 — Computer Science Schedule B2 — Mathematics and Computer Science 
Term 
Hilary Term 2012 (16 lectures) 
Overview
The course is addressed to both MSc students (in Mathematics, CS and MFoCS) and third year undergarduate students (in any of the following fields: Maths, CS, Maths and Comp, MMath, and Maths and Philosophy), with an interest in Logic, AI and the dynamics of information in multiagent systems. It explores and compares various logical approaches to information flows based on the use of modal logics, on formal languages for the specification of knowledgerelated features of a system, and on the use of sequent calculi and proof theory as well as their order theoretic algebraic semantics, as abstract models for information update. A range of important mathematical techniques, such as soundness, completeness, building proof trees, using algebraic axioms via rewriitng, and concepts, such as uncertainty, belief, knowledge, update, are introduced and explained. The course presents applications of these notions to the analysis of information update, communication, and navigation, and of the role of beliefs and beliefchanging actions, in the overall dynamics of any "society" of intelligent agents. In particular, we will model and reason about epistemic puzzles, robot navigation protocols, verification of protocols of unmanned vehicles, communication between unreliable or adversary agents over insecure channels. Implementation of these applications are studied by presenting rule based systems based on the sequent calculus and rewrite systems based on the algebra.
Learning outcomes
At the end of the course students are expected to:
 Analyze and model interactive scenarios of multiagent information systems and reason about them using the formal logics
 Learn syntax, proof systems and algebraic semantics for modal logics of actions and propostions
 Become able to reason about epistemic attitudes such as uncertainty, belief, knowledge and their update as a result of communication and navigation
 Derive dynamic properties of information, using the presented proof system and by drawing proof trees.
 Prove the above properties using the algebraic axiomatics in the form of rewrite rules
 Implement the proof rules and algebraic axioms using rulebased programming languages such as Prolog and Haskel
 Become familar with epistemic puzzles, navigation protcols, and protocols of unmanned vehicles, used as test cases of the course
Synopsis
Week 1. Examples of multiagent systems and scenarios: NASA Deep Space shuttle, air traffic control, eBay, Amazon, epistemic puzzles, security protocols, UAV protocols, robot navigation protocols
Week 2. Syntax and proof theory for a modal logic of actions, examples from puzzles and protocols
Week 3. Synax and proof theory for a modal logic of propositions, examples from puzzles and protocols
Week 4. Assumption Rules
Week 5. Modeling the muddy children puzzle and solving it
Week 6. Algebraic semantics for the modal logic of actions
Weeks 7. Algebraic semantics for the modal logic
of propositions
Week 8. Modelling a robot navigation protocol and proving its properties
Reading list
Introductory Reading: Modal logics of propostions and actions
 Chapters 1,2,3 of: R. Fagin, J, Halpern, Y. Moses, M. Vardi. Reasoning about Knowledge, MIT Press, 1995.
 Chapter 5 of D. Harel, D. Kozen, J. Tiuryn. Dynamic Logic, The MIT Press, 2000.
 Cahpters 1 to 5 of P. Blackburn, M. de Rijke, Y. Venema. Modal logic, Cambridge University Press, 2001.
Sequent Calculi for modal logics of actions and propositions
 to be updated
Algebraic Semantics for modal logics of actions and propositions
 to be updated
Further Reading: MultiAgent Systems
 M. Wooldridge. An Introduction to Multiagent Systems, John Wiley & Sons, 2002. (slides of a course based on this book are available from http://www.csc.liv.ac.uk/~mjw/pubs/imas/distrib/)