Examples of symplectic structures.
Nous donnons des exemples de feuilletages de Lie sur une variété compacte qui ne se déforment pas en des feuilletages de Lie à holonomie discrète.
A topological obstruction for a foliation be a sub-foliation of another is given by comparing the images of the associated characteristic homomorphisms (in the sense of Lehmann).
The archetype for the questions considered is: “Which plane oriented curves in the plane are representable as the images of the boundary of a disk under holomorphic function?” This question is equivalent to: “Which immersion of the circle in the plane are extendable to smooth sense preserving (= non-negative jacobian) mappings of the closed disk with the jacobian positive on the boundary?”The second question is generalized in terms of the genus and dimension of the source and target. An exposition...
A subsheaf of the sheaf of germs functions over an open subset of is called a sheaf of sub function. Comparing with the investigations of sheaves of ideals of , we study the finite presentability of certain sheaves of sub -rings. Especially we treat the sheaf defined by the distribution of Mather’s -classes of a mapping.