Parisian Master of Research in Computer Science
Master Parisien de Recherche en Informatique (MPRI)


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cours:c-2-3-3 [2011/07/12 19:26] (current)
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 +===== Bigraphs -- unifying models of mobile interaction (12h, 2 ECTS) =====
 +Responsible: [[|Robin Milner]], 
 +professor, Ecole Polytechnique
 +The course will be held in english. The venue is Room OC2, 175 rue du Chevaleret;
 +time 16h15--19h15; dates 8,15,22,29 January 2007.  All are welcome.
 +The lecture notes are at ;
 +slides for the first half of the course are at ; 
 +slides for the last half are at . 
 +Exercises on each chapter will be handed out, and the last hour each week will be spent trying them.  
 +(Solutions will be available probably a week later.) 
 +NEW, 19/01/07: Exercises for the first half of the course are now at , and for the second half at . 
 +There won't be time to cover everything in the notes.  
 +Comments are welcome from anyone at any time.
 +==== Summary ====
 +There has been recently a surge in ideas for how to model mobile
 +interaction, not only in informatic systems but even in
 +biology. Algebraic calculi are playing a strong part in this
 +development.  With the new ideas comes a problem of unity. As yet 
 +there is no canonical way to handle mobility, and we need much more 
 +experiment --- both in logic and algebra and in attempted 
 +applications --- before we can solve this problem.
 +Bigraphs are effort towards this unity.  They build upon existing
 +models, which show two kinds of mobility. There is the mobility of 
 +linkage, or connectivity, represented by the pi calculus; and there 
 +is the spatial mobility pioneered by mobile ambients.  Bigraphs 
 +reflect this duality in the mathematical structures involved.  They 
 +also try to unite the spatial metaphors that are found throughout 
 +computing (even sequential computing: think of locations, pointers, 
 +storage, scope, nesting, heap, ...) with phenomena of physical
 +space (think of building structure, plant structure, sensor 
 +networks, ...).
 +The course will begin with simple examples of modelling physical 
 +space and movement.  This will move rapidly to a model based upon 
 +elementary category theory; this seems to be the best way to 
 +represent the modularity in spatial structure and the way it
 +changes. The next example is direct presentation of CCS, showing 
 +how we can recover some of the theory for existing models, and even 
 +enrich them. A strong focus of the course is on recovering 
 +behavioural equivalence, such as bisimilarity, in a uniform way. 
 +The result for CCS is encouraging and does not require difficult 
 +mathematics. This completes Part I of the course.
 +Part II begins by enriching the mathematics not only to handle 
 +system structure algebraically, but also to handle the notion 
 +of occurrence of one system within another.  This will be essential 
 +to model the way the elements of a mobile system (nodes, processes
 +or other kinds of substructure) retain their identity as the system
 +reconfigures itself. We use a simple categorical construction
 +that also underpins a uniform treatment of transition systems, and
 +hence of behavioural equivalence.  The techniques are illustrated 
 +by application to Petri nets --- which, though not mobile, do 
 +provide a further test of the use of bigraphs. 
 +The course aims to deal with these theories and applications in 
 +some detail, with plenty of exercises.  The aim is not to rush 
 +through a predetermined amount, but to deal with the material in 
 +whatever depth it needs.  
 +Many of the ideas of bigraphs were worked out with James Leifer and
 +Ole Hogh Jensen over the past decade.  There will be a citation 
 +list, and also a complete text written with this course in mind.
 +==== Prerequisites ====
 +There is no strong mathematical prerequisite (e.g. the category
 +theory is elementary), but an interest in mathematical modelling will
 +be very helpful.
 +==== Related courses ====
 +2-3: This course treats related topics and the student may find in 
 +them interesting connections and useful background knowledge. However 
 +it is not required, since our course will be self-contained
 +==== References ====
 +==== Les années précédentes ====
 +   * [[2009-2010-C-2-3-3|Année 2009-2010]]
 +   * [[2008-2009-C-2-3-3|Année 2008-2009]]
 +   * [[2007-2008-C-2-3-3|Année 2007-2008]]
 +   * [[2006-2007-C-2-3-3|Année 2006-2007]]
 +   * Set ALLOWTOPICCHANGE = %MAINWEB%.WebMastersGroup, %MAINWEB%.RobinMilner
Universités partenaires Université Paris-Diderot
Université Paris-Saclay
ENS Cachan École polytechnique Télécom ParisTech
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