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Nous proposons une méthode de dévissage de la forme de Seifert d'un germe de courbe plane. Sous certaines hypothèses techniques, nous expliquons comment trouver le(s) type(s) topologique(s) des germes associés à la forme de Seifert d'un germe de courbe plane à deux branches. Réciproquement, nous démontrons que deux germes de courbe plane à deux branches, qui sont “isomères”, ont des formes de Seifert entières isomorphes. La filtration par le poids sur l'homologie entière de la fibre de Milnor est l'ingrédient clé de la démonstration.

A devissage method for the Seifert form of a plane curve germ is proposed. Assuming certain technical hypotheses, it is explained how one can find the topological type(s) of germs associated with the Seifert form of a given plane curve germ with two branches. Conversely, two plane curve germs with two branches, which are “isomeric”, are shown to have isomorphic integral Seifert forms. The weight filtration on the integral homology of the Milnor fiber is the key ingredient of the proof.

Within the qualitative approach to the study of finite particle quantum systems different possible ways of the generalization of Hamiltonian monodromy are discussed. It is demonstrated how several simple integrable models like non-linearly coupled resonant oscillators, or coupled rotators, lead to physically natural generalizations of the monodromy concept. Fractional monodromy, bidromy, and the monodromy in the case of multi-valued energy-momentum maps are briefly reviewed.