Nous définissons une structure logique permettant de représenter les classes d’homéomorphismes des arrangements de pseudodroites du plan euclidien. Nous donnons une axiomatisation finie du premier ordre de la réalisabilité des arrangements de pseudodroites.
We design algorithms of “optimal" for several natural problems about first-order queries on structures of bounded degree. For that purpose, we first introduce a framework to deal with logical or combinatorial problems whose instances may admit of several solutions . One associates to such a problem several specific tasks: compute a (for the uniform probability distribution) solution ; without repetition each solution in some specific linear order where ; compute the solution...
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