Election, Naming and Cellular Edge Local Computations

International audienceWe examine the power and limitations of the weakest vertex relabelling system which allows to change a label of a vertex in function of its own label and of the label of one of its neighbours. We characterise the graphs for which two important distributed algorithmic problems are solvable in this model: naming and election

GT-VC 2005 Preliminary Version Semi-local model of computations on graphs to break the local symmetry Work in Progress

Abstract We consider finite connected undirected graphs without self-loops as a model of computer networks. The nodes of the graph represent computers or processors, while the edges of the graph correspond to the links between them. We present a model of distributed computations, called semi-local. This extension of the classical local model breaks the local symmetry. As a result, many useful tasks become deterministically solvable in every network assuming a very small initial knowledge about its graph representation. One of these tasks is a creation of a token in an arbitrary anonymous ring -an example of election of a leader. A semi-local solution to this problem is presented